100 High-Scoring MCQs on Force and Motion (Set - 1) | Class 11 Physics | Unit 3 | FBISE

This post contains 100 carefully selected multiple-choice questions (MCQs) from Unit-3: Force and Motion of Class 11 Physics, designed strictly according to the FBISE syllabus. These MCQs include a well-balanced mix of conceptual and numerical problems, making them exam-ready, revision-friendly, and high-scoring.

Whether you are preparing for annual board examinations, chapter tests, or competitive entry tests, this comprehensive MCQ collection thoroughly covers all the fundamental principles of motion, forces, and Newtonian mechanics, enabling students to master the chapter with confidence and accuracy.

This unit-wise MCQ set includes questions from:

Vector nature of displacement and comparison with distance
Average and instantaneous speed and velocity
Interpretation of displacement–time and velocity–time graphs
Determination of instantaneous velocity and acceleration using graph slopes
Uniform and non-uniform acceleration, including positive and negative acceleration
Equations of uniformly accelerated motion and their numerical applications
Free fall and motion under gravity
Projectile motion as two-dimensional motion in a vertical plane
Horizontal and vertical components of projectile motion and their independence
Maximum height, time of flight, range, and position of a projectile at a given time
Launch angle for maximum range and relation between complementary angles
Effect of air resistance on projectile motion
Newton’s laws of motion and their applications in daily life
Concept of mass, inertia, and weight in a gravitational field
Momentum, impulse, and Newton’s second law as rate of change of momentum
Conservation of momentum and its relation to Newton’s third law
Elastic and inelastic collisions in one dimension
Real-life applications such as airbags, catching balls, recoil of guns, and safety devices

Each MCQ is provided with the correct answer and a clear, concise explanation, helping students:

Strengthen conceptual understanding
Avoid common exam mistakes
Improve numerical problem-solving skills
Achieve maximum marks in the MCQs section

MCQs No. 1

In projectile motion, the horizontal component of velocity __________ throughout the flight.

a. Increases
b. Decreases
c. Remains constant
d. None of these

Correct Answer: c. Remains constant

Explanation:
In the absence of air resistance, no force acts in the horizontal direction. Hence, horizontal acceleration is zero and horizontal velocity remains constant.

MCQs No. 2

Impulse has the same unit as:

a. Force
b. Energy
c. Momentum
d. None of these

Correct Answer: c. Momentum

Explanation:
Impulse = Force × Time = Change in momentum.
Therefore, impulse and momentum have the same unit (kg m s⁻¹).

MCQs No. 3

A projectile is thrown so that it travels a maximum range of 1000 m. How high will it rise?

a. 400 m
b. 800 m
c. 500 m
d. 250 m

Correct Answer: d. 250 m

Explanation:
For maximum range, angle of projection θ = 45°.

R = \frac{u^2}{g}, \quad H = \frac{u^2}{4g}

Hence,

H = \frac{R}{4} = \frac{1000}{4} = 250 \text{ m}

MCQs No. 4

The slope of a displacement–time graph represents:

a. Distance
b. Velocity
c. Acceleration
d. None of these

Correct Answer: b. Velocity

Explanation:
Slope = change in displacement / change in time = velocity.

MCQs No. 5

The rate of change of linear momentum of a freely falling body is equal to:

a. Weight
b. Power
c. Inertia
d. Impulse

Correct Answer: a. Weight

Explanation:
Rate of change of momentum = Force.
For a freely falling body, the force acting is weight (mg).

MCQs No. 6

A missile is fired with a speed of 98 m/s at an angle of 30° with the horizontal. The time for which the missile remains airborne is:

a. 196 m
b. 10 s
c. 98 s
d. 2940 s

Correct Answer: b. 10 s

Explanation:

T = \frac{2u\sin\theta}{g}

T = \frac{2(98)\sin30^\circ}{9.8} = \frac{98}{9.8} = 10 \text{ s}

MCQs No. 7

Two projectiles are in flight at the same time. The acceleration of one relative to the other is:

a. Always 9.8 m/s²
b. Can be horizontal
c. Can be as large as 19.6 m/s²
d. Zero

Correct Answer: d. Zero

Explanation:
Both projectiles experience the same gravitational acceleration. Hence, relative acceleration is zero.

MCQs No. 8

The angle of projection for which the range of a projectile is equal to its maximum height is:

a. tan⁻¹(1/4)
b. tan⁻¹(4)
c. tan⁻¹(1/2)
d. tan⁻¹(2)

Correct Answer: b. tan⁻¹(4)

Explanation:
When R=H:

\tan\theta = 4

MCQs No. 9

If the velocity–time graph is a straight line parallel to the time axis, then:

a. Acceleration is constant
b. Acceleration is zero
c. Acceleration is variable
d. Velocity is zero

Correct Answer: b. Acceleration is zero

Explanation:
Slope of velocity–time graph represents acceleration. A horizontal line means zero slope.

MCQs No. 10

Two blocks of masses 1 kg and 3 kg are in contact and acted upon by a force of 40 N. The acceleration of the system is:

a. 40 m/s²
b. 10 m/s²
c. 30 m/s²
d. 50 m/s²

Correct Answer: b. 10 m/s²

Explanation:

a = \frac{F}{m_1 + m_2} = \frac{40}{1+3} = 10 \text{ m/s}^2

MCQs No. 11

When a body is in motion, which of the following always changes?

a. Velocity
b. Acceleration
c. Position vector
d. Momentum

Correct Answer: c. Position vector

Explanation:
A moving body continuously changes its position with time, even if velocity or acceleration remains constant.

MCQs No. 12

A bomber drops a bomb when it is vertically above the target. It misses the target due to:

a. Vertical component of velocity
b. Force of gravity
c. Horizontal component of velocity of bomber
d. None of these

Correct Answer: c. Horizontal component of velocity of bomber

Explanation:
Due to inertia, the bomb retains the horizontal velocity of the bomber and moves forward.

MCQs No. 13

An elastic collision involves:

a. Loss of energy
b. Gain of energy
c. No relation with energy
d. No gain or loss of energy

Correct Answer: d. No gain or loss of energy

Explanation:
In elastic collisions, both momentum and kinetic energy are conserved.

MCQs No. 14

The time required by a projectile to reach the maximum height is:

a. $\sqrt{\frac{8H}{g}}$
b. $\sqrt{\frac{4H}{g}}$
c. $\sqrt{\frac{2H}{g}}$
d. $\sqrt{\frac{H}{g}}$

Correct Answer: c. $\sqrt{\frac{2H}{g}}$

Explanation:

H = \frac{u^2 \sin^2\theta}{2g} \Rightarrow t = \frac{u\sin\theta}{g} = \sqrt{\frac{2H}{g}}

MCQs No. 15

If two cars move in opposite directions with speeds 10 m/s and 5 m/s, their relative velocity is:

a. 5 m/s
b. –5 m/s
c. 10 m/s
d. 15 m/s

Correct Answer: d. 15 m/s

Explanation:
For opposite directions:

v_{\text{relative}} = v_1 + v_2 = 10 + 5 = 15 \text{ m/s}

MCQs No. 16

The horizontal range of a projectile at a certain place is completely determined by:

a. The angle of projection
b. The height of the projectile
c. The mass of the projectile
d. Speed and angle of projection

Correct Answer: d. Speed and angle of projection

Explanation:

R = \frac{u^2 \sin 2\theta}{g}

Hence, horizontal range depends only on initial speed and angle of projection, not on mass or height.

MCQs No. 17

When two bodies move towards each other with constant speeds, the distance between them decreases at 6 m/s. If they move in the same direction, the distance between them increases at 4 m/s. Their speeds are:

a. 5 m/s, 1 m/s
b. 6 m/s, 1 m/s
c. 3 m/s, 3 m/s
d. 4 m/s, 2 m/s

Correct Answer: a. 5 m/s, 1 m/s

Explanation:
Let v₁ and v₂ be their speeds:

v_1 + v_2 = 6 \quad (\text{opposite direction})

v_1 - v_2 = 4 \quad (\text{same direction})

Solving: v₁ = 5 m/s, v₂ = 1 m/s.

MCQs No. 18

The conditions under which equations of motion can be applied are:

a. Motion should be one-dimensional
b. Acceleration should be uniform
c. Frame of reference should be inertial
d. All of the above

Correct Answer: d. All of the above

Explanation:
Equations of motion (s = vᵢt + ½ at² etc.) are valid only in uniform acceleration and inertial frames, in one-dimensional motion.

MCQs No. 19

Newton’s second law of motion gives the definition of:

a. Momentum
b. Acceleration
c. Velocity
d. Both a and b

Correct Answer: b. Acceleration

Explanation:

F = \frac{dp}{dt} \Rightarrow F = ma

Hence, Newton’s second law defines acceleration as rate of change of velocity.

MCQs No. 20

The motion of a rocket in space is in accordance with the law of conservation of:

a. Energy
b. Charge
c. Mass
d. Momentum

Correct Answer: d. Momentum

Explanation:
In absence of external force, the linear momentum of the system remains constant (p_initial = p_final).

MCQs No. 21

Quantities remaining constant in a collision are:

a. Momentum, kinetic energy, and temperature
b. Momentum, kinetic energy but not temperature
c. Momentum, temperature but not kinetic energy
d. Momentum but neither kinetic energy nor temperature

Correct Answer: d. Momentum but neither kinetic energy nor temperature

Explanation:
Momentum is always conserved in collisions. Kinetic energy is conserved only in elastic collisions.

MCQs No. 22

A fireman wants to slide down a rope whose breaking strength is ¾ of his weight. The minimum acceleration he should have is:

a. ¾ g
b. ½ g
c. ¼ g
d. 0

Correct Answer: c. ¼ g

Explanation:

F = W - T = mg - \frac{3}{4} mg = \frac{1}{4} mg

a = F/m = 1/4 g

MCQs No. 23

A 2 N force acts on a mass. If the momentum of the mass changes by 120 kg·m/s, the force acts for:

a. 8 s
b. 30 s
c. 60 s
d. 120 s

Correct Answer: c. 60 s

Explanation:

F = \frac{\Delta p}{\Delta t} \Rightarrow \Delta t = \frac{\Delta p}{F} = \frac{120}{2} = 60 \text{ s}

MCQs No. 24

The property of a moving object by virtue of which it resists changes in motion is called:

a. Inertia of the body
b. Quantity of motion
c. Acceleration of the body
d. All of these

Correct Answer: a. Inertia of the body

Explanation:
Inertia is the tendency of a body to resist any change in its state of motion.

MCQs No. 25

The force experienced by a wall struck normally by water with speed 10 m/s and flow rate 0.0001 m³/s is:

a. 1 N
b. 10 N
c. 100 N
d. None

Correct Answer: a. 1 N

Explanation:

F = \frac{\Delta p}{\Delta t} = V \cdot \frac{\Delta m}{\Delta t} = 10 \times 0.0001 \times 1000 = 1 \text{ N}

MCQs No. 26

The distance covered by a body starting from rest in time t is:

a. $\frac{1}{2} a t^2$
b. v t
c. a t
d. $\frac{1}{3} a t^2$

Correct Answer: a. $\frac{1}{2} a t^2$

Explanation:
Equation of motion for constant acceleration from rest:

s = ut + \frac{1}{2} a t^2 = 0 + \frac{1}{2} a t^2

MCQs No. 27

The angle between the centripetal force $F_C$ and momentum $\vec{p}$ in circular motion is:

a. 90°
b. 0°
c. 180°
d. 30°

Correct Answer: a. 90°

Explanation:
Centripetal force acts toward the center, momentum is tangential, so angle between them = 90°.

MCQs No. 28

The range of a projectile on a horizontal plane is the same for which pair of angles?

a. 30° and 60°
b. 20° and 80°
c. 0° and 45°
d. 10° and 90°

Correct Answer: a. 30° and 60°

Explanation:
For projectile motion, complementary angles (θ and 90°−θ) produce the same range.

MCQs No. 29

A rock is dropped from a height. After 3 s of free fall, its speed is:

a. 30 m/s
b. 29.4 m/s
c. 2940 m/s
d. 50 m/s

Correct Answer: b. 29.4 m/s

Explanation:

v = u + gt = 0 + 9.8 \times 3 = 29.4 \text{ m/s}

MCQs No. 30

The correct relation between time of flight T and height H of a projectile is:

a. $H = \frac{g T^2}{8}$

b. $H = \frac{8 T^2}{g}$

c. $H = \frac{8 g}{T^2}$

d. $H = \frac{8}{g T^2}$

Correct Answer: a. $H = \frac{g T^2}{8}$

Explanation:
Time to reach maximum height $T/2 = \sqrt{2H/g}$

hence H = g T² / 8.

MCQs No. 31

A cricket ball is hit at 45° to the horizontal with kinetic energy $E$ . The kinetic energy at the highest point is:

a. 0
b. E/2
c. $E/\sqrt{2}$
d. E

Correct Answer: b. E/2

Explanation:
At the highest point, the vertical component of velocity is zero, only horizontal component remains.

K.E._\text{horizontal} = \frac{1}{2} m v_x^2 = \frac{1}{2} E

MCQs No. 32

The velocity of a projectile at maximum height is:

a. Zero
b. Minimum
c. Maximum
d. Between maximum and minimum

Correct Answer: b. Minimum

Explanation:
At maximum height, vertical velocity = 0, but horizontal component remains. Hence, velocity is minimum (not zero).

MCQs No. 33

The slope of a displacement–time graph represents:

a. Velocity
b. Acceleration
c. Position vector
d. Momentum

Correct Answer: a. Velocity

Explanation:
Slope = Δx/Δt = velocity. Acceleration would be the slope of a velocity–time graph.

MCQs No. 34

A shell of mass $m$ moving with velocity $V$ suddenly breaks into two pieces. The velocity of the larger piece (mass 3m/4) is:

a. V
b. 2V
c. 3V/4
d. 4V/3

Correct Answer: d. 4V/3

Explanation:
Using conservation of momentum:

mv = \frac{m}{4}v_1 + \frac{3m}{4}v_2

Assuming smaller piece initially at rest, solve: $v_2 = 4V/3$ .

MCQs No. 35

A rubber ball is dropped from a height of 5 m on a planet where gravity is unknown. On bouncing, it rises to 1.8 m. The ball loses velocity on bouncing by a factor of:

a. 16/25
b. 2/5
c. 3/5
d. 9/25

Correct Answer: c. 3/5

Explanation:

\frac{v_2}{v_1} = \sqrt{\frac{h_2}{h_1}} = \sqrt{\frac{1.8}{5}} = 0.6 = 3/5

MCQs No. 36

A person travels a distance $x = 20t + 2At^2$ , where $A$ is constant. The acceleration of the person is:

a. A/4 m/s²
b. 4/A m/s²
c. 4 m/s²
d. 4A m/s²

Correct Answer: d. 4A m/s²

Explanation:
Compare $x = ut + ½ a t^2$ with $x = 20t + 2At^2$ :

\frac{1}{2}a = 2A \Rightarrow a = 4A

MCQs No. 37

The symbol $g$ represents acceleration due to gravity. Which statement is correct?

a. g is gravity
b. g is the ratio of weight/mass
c. g is the weight of an object
d. g is reduced by air resistance

Correct Answer: b. g is the ratio of weight/mass

Explanation:

g = \frac{W}{m} \quad (W = mg)

MCQs No. 38

A car travels a distance S on a straight road in 2 hours and returns in 3 hours. Its average velocity is:

a. 2/5 m/s
b. 2.5/5 m/s
c. (2/5) + (3/5) m/s
d. 0

Correct Answer: d. 0

Explanation:
Average velocity = total displacement / total time. Round trip displacement = 0, so average velocity = 0.

MCQs No. 39

A racing car accelerates uniformly through three gears with average speeds 20 m/s for 2 s, 40 m/s for 2 s, and 60 m/s for 6 s. What is the overall average speed?

a. 12 m/s
b. 13.3 m/s
c. 40 m/s
d. 48 m/s

Correct Answer: d. 48 m/s

Explanation:

\bar{v} = \frac{\sum v_i t_i}{\sum t_i} = \frac{20*2 + 40*2 + 60*6}{2+2+6} = \frac{20*2+40*2+60*6}{10} = 48 \text{ m/s}

MCQs No. 40

A monkey descends from a branch with the branch’s breaking strength 75% of the monkey’s weight. Minimum acceleration without breaking the branch:

a. 3/4 g
b. 1/2 g
c. 0
d. 1/4 g

Correct Answer: d. 1/4 g

Explanation:

F = W - T = mg - 0.75 mg = 0.25 mg \Rightarrow a = 0.25 g

MCQs No. 41

The shape of the velocity–time graph for constant acceleration is:

a. Straight line
b. Parabola
c. Hyperbola
d. Ellipse

Correct Answer: a. Straight line

Explanation:
For constant acceleration, v ∝ t → straight line.

MCQs No. 42

The area under a velocity–time graph represents:

a. Force
b. Momentum
c. Distance
d. None

Correct Answer: c. Distance

Explanation:
Area under v–t graph = v × t = displacement (distance for straight line).

MCQs No. 43

A mass accelerated uniformly experiences a resultant force that is:

a. Zero
b. Constant but not zero
c. Increasing uniformly
d. Both a and b

Correct Answer: b. Constant but not zero

Explanation:
Newton’s 2nd law: F = ma. For constant acceleration, F is constant and non-zero.

MCQs No. 44

Newton’s 3rd law explains:

a. Effect of force
b. Existence of force
c. Loss of force
d. Existence of pair of forces in nature

Correct Answer: d. Existence of pair of forces in nature

Explanation:
Every action has an equal and opposite reaction.

MCQs No. 45

The Newton is the unit of:

a. Work
b. Angular
c. Power
d. Rate of change of linear momentum

Correct Answer: d. Rate of change of linear momentum

Explanation:

1\text{ N} = 1\,kg\,m/s^2 = \frac{\Delta p}{\Delta t}

MCQs No. 46

A motorcycle safety helmet extends the time of collision, thereby decreasing:

a. Chance
b. Force acting
c. Velocity
d. Impulse

Correct Answer: b. Force acting

Explanation:

I = F \Delta t \Rightarrow F = \frac{I}{\Delta t}

Increasing Δt decreases F.

MCQs No. 47

A constant force F is applied on a body for a time Δt. Impulse is:

a. $-m(V_f^2 - V_i^2)$

b. $\frac{m(V_f - V_i)}{\Delta t}$

c. $\frac{\Delta t}{ma}$

d. $\frac{ma}{t}$

Correct Answer: b. $\frac{m(V_f - V_i)}{\Delta t}$

Explanation:

I = F \Delta t = \Delta p = m(V_f - V_i)

MCQs No. 48

A bullet of mass $m$ moving with velocity $V$ is fired into a large wooden block of mass $M$ . If the bullet remains embedded, the velocity of the system will be:

a. $\frac{m}{M+m}V$

b. $\frac{M+m}{m}V$

c. $\frac{m}{M+m} \, V$

d. $\frac{M}{M-m}V$

Correct Answer: a. $\frac{m}{M+m} V$

Explanation:
By conservation of momentum:

mV + M(0) = (M + m)V_f \Rightarrow V_f = \frac{m}{M+m} V

MCQs No. 49

Conservation of linear momentum is equivalent to:

a. Newton 1st Law
b. Newton 2nd Law
c. Newton 3rd Law
d. None

Correct Answer: a. Newton 1st Law

Explanation:
Momentum is conserved when net external force = 0, which is a direct application of Newton’s First Law.

MCQs No. 50

A particle of mass $m$ moving with velocity $V$ makes a head-on elastic collision with another particle of the same mass initially at rest. The velocity of the first particle after collision is:

a. 2V
b. -V
c. +V
d. 0

Correct Answer: d. 0

Explanation:
For equal masses in a head-on elastic collision:

v_1' = \frac{m_1 - m_2}{m_1 + m_2} V_1 + \frac{2 m_2}{m_1 + m_2} V_2 = \frac{m - m}{2m} V_1 + \frac{2m}{2m} (0) = 0

MCQs No. 51

The horizontal range of a projectile is:

a. $\frac{2 V_i^2}{g}$

b. $\frac{2 V_i^2}{g} \sin \theta$

c. $\frac{V_i^2}{g}$

d. $\frac{2 V_{i}^{2}}{g} \sin 2 θ$

Correct Answer: d. $\frac{2 V_i^2}{g} \sin 2\theta$

Explanation:
Range formula for projectile:

R = \frac{V_i^2 \sin 2\theta}{g}

This gives the horizontal distance covered.

MCQs No. 52

A bomb is dropped from an airplane moving horizontally at 200 mph. If air resistance is negligible, the bomb will reach the ground in 5 s. The altitude is:

a. 4 miles
b. 122.5 m
c. 40 m
d. 10 m

Correct Answer: b. 122.5 m

Explanation:

H = \frac{1}{2} g t^2 = \frac{1}{2} (9.8)(5^2) = 122.5 \text{ m}

MCQs No. 53

The study of projectile motion is called:

a. Meta–Physics
b. Particle Physics
c. Projectile Physics
d. Ballistics

Correct Answer: d. Ballistics

Explanation:
Ballistics is the science of projectiles in motion.

MCQs No. 54

To change the momentum of an object, there must be:

a. A force applied
b. Change in time
c. Change in distance
d. Change in temperature

Correct Answer: a. A force applied

Explanation:
$\Delta p = F \Delta t$ . Momentum changes only if force is applied.

MCQs No. 55

A basketball is thrown upward along a parabolic path. What is the ball’s acceleration at the highest point?

a. 0
b. ½ horizontal
c. g upward
d. g downward

Correct Answer: d. g downward

Explanation:
Acceleration due to gravity always acts downward, even at the top of the path.

MCQs No. 56

A projectile is thrown to travel maximum range of 1000 m. How high will it rise?

a. 500 m
b. 250 m
c. None of these

Correct Answer: c. None of these

Explanation:
Maximum height depends on vertical component:

H = \frac{(V \sin \theta)^2}{2g}

Without angle, height cannot be determined.

MCQs No. 57

Which does not change when a force is applied on a body?

a. Mass
b. Velocity
c. Position
d. Acceleration

Correct Answer: a. Mass

Explanation:
Mass is inherent property and does not change; all others can change due to force.

MCQs No. 58

In projectile motion, the horizontal component of velocity:

a. Increases
b. Decreases
c. Remains constant
d. None of these

Correct Answer: c. Remains constant

Explanation:
Horizontal velocity is unaffected by gravity in absence of air resistance.

MCQs No. 59

A projectile is thrown so that it travels 1000 m. How high will it rise?

a. 400 m
b. 800 m
c. 500 m
d. 250 m

Correct Answer: None of these

Explanation:
Vertical height requires vertical component of velocity; range alone is insufficient.

MCQs No. 60

The slope of a displacement–time graph is called:

a. Distance
b. Velocity
c. Acceleration
d. None of these

Correct Answer: b. Velocity

Explanation:
Slope = Δx/Δt = velocity.

MCQs No. 61

The rate of change in linear momentum for a freely falling body is equal to:

a. Weight
b. Power
c. Inertia
d. Impulse

Correct Answer: a. Weight

Explanation:
$\frac{dp}{dt} = m \frac{dv}{dt} = mg$

MCQs No. 62

A car accelerates uniformly from 10 m/s to 30 m/s in 5 seconds. Its acceleration is:

a. 2 m/s²
b. 4 m/s²
c. 6 m/s²
d. 8 m/s²

Correct Answer: b. 4 m/s²

Explanation:

a = \frac{\Delta v}{\Delta t} = \frac{30-10}{5} = 4 \text{ m/s²}

MCQs No. 63

A particle moves along a straight line such that $x = 5t^2 + 2t$ . Its instantaneous velocity at t = 2 s is:

a. 12 m/s
b. 22 m/s
c. 24 m/s
d. 20 m/s

Correct Answer: b. 22 m/s

Explanation:

v = \frac{dx}{dt} = 10t + 2 \Rightarrow v = 10(2)+2 = 22 \text{ m/s}

MCQs No. 64

A particle moves in uniform acceleration from rest, covering 100 m in 5 s. Its acceleration is:

a. 6 m/s²
b. 8 m/s²
c. 10 m/s²
d. 12 m/s²

Correct Answer: b. 8 m/s²

Explanation:

s = \frac{1}{2} a t^2 \Rightarrow a = \frac{2s}{t^2} = \frac{2 \cdot 100}{25} = 8

MCQs No. 65

Two objects of masses 2 kg and 3 kg collide elastically. If the first mass moves at 4 m/s towards the second at rest, the velocity of the second after collision is:

a. 1.6 m/s
b. 2.4 m/s
c. 3.2 m/s
d. 4 m/s

Correct Answer: b. 2.4 m/s

Explanation:
Use elastic collision formula:

v_2' = \frac{2 m_1}{m_1 + m_2} v_1 = \frac{2 \cdot 2}{2+3} \cdot 4 = 2.4 \text{ m/s}

MCQs No. 66

The instantaneous acceleration of a body at the topmost point of a vertically thrown ball is:

a. Zero
b. g downward
c. g upward
d. 2g downward

Correct Answer: b. g downward

Explanation:
Acceleration due to gravity always acts downward, regardless of velocity.

MCQs No. 67

A body moves in a circle of radius 5 m at constant speed 10 m/s. Its centripetal acceleration is:

a. 10 m/s²
b. 20 m/s²
c. 15 m/s²
d. 25 m/s²

Correct Answer: d. 20 m/s²

Explanation:

a_c = \frac{v^2}{r} = \frac{10^2}{5} = 20 \text{ m/s²}

MCQs No. 68

Two projectiles are fired at 45° and 60° with the same speed. The one with maximum range is:

a. 45°
b. 60°
c. 30°
d. 90°

Correct Answer: a. 45°

Explanation:
Maximum range occurs at 45° for a given initial speed.

MCQs No. 69

If a particle moves such that its displacement is $x = 3t^3$ , the instantaneous acceleration is:

a. 9t
b. 18t
c. 3t²
d. 9t³

Correct Answer: b. 18t

Explanation:

v = d x / d t = 9 t^{2} \Rightarrow a = d v / d t = 18 t

MCQs No. 70

A particle is thrown vertically upward with speed 20 m/s. Time to reach maximum height:

a. 1 s
b. 2 s
c. 3 s
d. 4 s

Correct Answer: b. 2 s

Explanation:

t_\text{up} = \frac{v}{g} = \frac{20}{9.8} \approx 2 \text{ s}

MCQs No. 71

A car moves with uniform acceleration and covers 40 m in 4 s, starting from rest. Its acceleration is:

a. 2 m/s²
b. 4 m/s²
c. 5 m/s²
d. 8 m/s²

Correct Answer: c. 5 m/s²

Explanation:

s = \frac{1}{2} at^2 \Rightarrow a = \frac{2 \cdot 40}{16} = 5 \text{ m/s²}

MCQs No. 72

The slope of a velocity–time graph gives:

a. Distance
b. Speed
c. Acceleration
d. Momentum

Correct Answer: c. Acceleration

Explanation:
Slope = Δv/Δt = acceleration.

MCQs No. 73

A car moving at 30 m/s brakes to stop in 5 s. Average deceleration is:

a. 4 m/s²
b. 6 m/s²
c. 5 m/s²
d. 3 m/s²

Correct Answer: c. 6 m/s²

Explanation:

a = \frac{\Delta v}{\Delta t} = \frac{0-30}{5} = -6 \text{ m/s²}

MCQs No. 74

If the velocity–time graph of a particle is a horizontal straight line, the motion is:

a. Uniformly accelerated
b. Uniform velocity
c. Non-uniform velocity
d. At rest

Correct Answer: b. Uniform velocity

Explanation:
A horizontal v–t graph means velocity is constant and acceleration is zero.

MCQs No. 75

A ball is thrown vertically upward. At the highest point, its:

a. Velocity and acceleration both are zero
b. Velocity is zero but acceleration is maximum
c. Velocity is maximum and acceleration is zero
d. Both velocity and acceleration are maximum

Correct Answer: b. Velocity is zero but acceleration is maximum

Explanation:
Velocity becomes zero momentarily, but acceleration due to gravity remains g downward.

MCQs No. 76

Which quantity does NOT change in an elastic collision?

a. Kinetic energy
b. Momentum
c. Mechanical energy
d. Both a and b

Correct Answer: d. Both a and b

Explanation:
In elastic collision, both momentum and kinetic energy are conserved.

MCQs No. 77

The area under a displacement–time graph represents:

a. Velocity
b. Acceleration
c. Momentum
d. No physical quantity

Correct Answer: d. No physical quantity

Explanation:
Area under a displacement–time graph has no physical meaning.

MCQs No. 78

A projectile is fired horizontally. Its time of flight depends upon:

a. Horizontal velocity
b. Mass of projectile
c. Height of projection
d. Angle of projection

Correct Answer: c. Height of projection

Explanation:
Vertical motion determines time of flight; horizontal velocity does not affect it.

MCQs No. 79

Which of the following quantities is a vector?

a. Speed
b. Distance
c. Displacement
d. Time

Correct Answer: c. Displacement

Explanation:
Displacement has both magnitude and direction.

MCQs No. 80

A body moves with constant speed but changing velocity. This motion is:

a. Linear motion
b. Uniform motion
c. Circular motion
d. Oscillatory motion

Correct Answer: c. Circular motion

Explanation:
In circular motion, speed remains constant but direction changes, so velocity changes.

MCQs No. 81

A body of mass 5 kg moves with velocity 4 m/s. Its momentum is:

a. 9 kg·m/s
b. 20 kg·m/s
c. 25 kg·m/s
d. 40 kg·m/s

Correct Answer: b. 20 kg·m/s

Explanation:

p = mv = 5 \times 4 = 20 \text{ kg·m/s}

MCQs No. 82

Which graph represents uniformly accelerated motion?

a. Straight line s–t graph
b. Curved s–t graph
c. Horizontal v–t graph
d. Vertical v–t graph

Correct Answer: b. Curved s–t graph

Explanation:
Uniform acceleration produces a parabolic displacement–time graph.

MCQs No. 83

If net force acting on a body is zero, the body:

a. Must be at rest
b. Must be accelerating
c. Moves with constant velocity
d. Loses momentum

Correct Answer: c. Moves with constant velocity

Explanation:
Newton’s first law: zero net force → no change in velocity.

MCQs No. 84

A force of 10 N acts on a mass of 2 kg. Its acceleration is:

a. 5 m/s²
b. 10 m/s²
c. 20 m/s²
d. 2 m/s²

Correct Answer: a. 5 m/s²

Explanation:

a = \frac{F}{m} = \frac{10}{2} = 5 \text{ m/s²}

MCQs No. 85

Which law explains recoil of a gun?

a. Newton’s first law
b. Newton’s second law
c. Newton’s third law
d. Law of inertia

Correct Answer: c. Newton’s third law

Explanation:
Action and reaction forces are equal and opposite.

MCQs No. 86

A body falls freely from rest. Its velocity after 2 seconds is:

a. 9.8 m/s
b. 19.6 m/s
c. 29.4 m/s
d. 39.2 m/s

Correct Answer: b. 19.6 m/s

Explanation:

v = gt = 9.8 \times 2 = 19.6 \text{ m/s}

MCQs No. 87

The unit of impulse is equivalent to:

a. N
b. N·s
c. kg/m²
d. J/s

Correct Answer: b. N·s

Explanation:
Impulse = Force × Time = change in momentum.

MCQs No. 88

A body projected vertically upward returns to the ground. Total displacement is:

a. Maximum
b. Equal to distance
c. Zero
d. Half of distance

Correct Answer: c. Zero

Explanation:
Initial and final positions are same → displacement = 0.

MCQs No. 89

Which factor does NOT affect the range of a projectile (neglect air resistance)?

a. Initial speed
b. Angle of projection
c. Mass of projectile
d. Acceleration due to gravity

Correct Answer: c. Mass of projectile

Explanation:
Projectile motion is independent of mass.

MCQs No. 90

The slope of velocity–time graph at any point gives:

a. Speed
b. Distance
c. Acceleration
d. Momentum

Correct Answer: c. Acceleration

Explanation:
Slope = Δv/Δt = acceleration.

MCQs No. 91

A body moves with increasing speed but constant acceleration. Its velocity–time graph is:

a. Straight line
b. Curve
c. Circle
d. Horizontal line

Correct Answer: a. Straight line

Explanation:
Constant acceleration produces a straight v–t graph.

MCQs No. 92

If momentum of a system is conserved, the system must be:

a. Closed
b. Open
c. Accelerated
d. Non-isolated

Correct Answer: a. Closed

Explanation:
Momentum is conserved in isolated (closed) systems.

MCQs No. 93

A body projected at an angle θ has maximum range when θ equals:

a. 30°
b. 45°
c. 60°
d. 90°

Correct Answer: b. 45°

Explanation:
Maximum range occurs at 45°.

MCQs No. 94

Which quantity remains constant in uniform circular motion?

a. Velocity
b. Acceleration
c. Speed
d. Momentum

Correct Answer: c. Speed

Explanation:
Magnitude of velocity (speed) remains constant; direction changes.

MCQs No. 95

The impulse delivered to an object equals change in:

a. Energy
b. Velocity
c. Momentum
d. Force

Correct Answer: c. Momentum

Explanation:
Impulse = Δp.

MCQs No. 96

A body has zero acceleration. Which is possible?

a. Body is at rest
b. Body moves with constant velocity
c. Body is in equilibrium
d. All of these

Correct Answer: d. All of these

Explanation:
Zero acceleration means no change in velocity.

MCQs No. 97

The time of flight of a projectile depends on:

a. Horizontal velocity
b. Vertical component of velocity
c. Mass of projectile
d. Range

Correct Answer: b. Vertical component of velocity

Explanation:
Time of flight depends on vertical motion only.

MCQs No. 98

A moving body possesses inertia because of its:

a. Speed
b. Acceleration
c. Mass
d. Momentum

Correct Answer: c. Mass

Explanation:
Inertia is a property due to mass.

MCQs No. 99

Which collision has maximum loss of kinetic energy?

a. Elastic
b. Inelastic
c. Perfectly inelastic
d. Explosive

Correct Answer: c. Perfectly inelastic

Explanation:
In perfectly inelastic collision, bodies stick together causing maximum energy loss.

MCQs No. 100

Newton’s laws are not applicable when objects move:

a. Slowly
b. In vacuum
c. Near the speed of light
d. On Earth

Correct Answer: c. Near the speed of light

Explanation:
At relativistic speeds, classical mechanics fails.