Class 8 General Science Notes: - Unit-8: Force and Pressure: Solved Exercise (Short Questions and Answers)

(National Book Foundation - New Book/New Syllabus Based on National Curriculum Pakistan 2023-2024 and Onwards)

(Class 8 General Science Notes for 8th Centralized Exam 2023-2024 and onward, FDE, Islamabad)

B. Short Questions

i). If there are many forces acting on an object, how can the net force be ZERO?

Ans:

The net force is the total amount of force acting on an object. It becomes 0 (zero) when the forces are equal in magnitude but opposite in direction canceling each other out or balancing them.

ii). Why does stepping on a high-heeled shoe hurts more than a flat shoe?

Ans:

High-heeled shoes or boots transfer the force through a much smaller area, causing a much greater pressure. It will hurt more if a person steps on someone’s foot in high heels than if they are wearing flat shoes.

iii). Explain why objects moving in fluids must have special shapes.

Ans:

Objects moving in fluids face fluid friction. Therefore objects moving in fluids must have stream-lined shapes in order to reduce friction.

iv). Consider two identical pails of water filled to the brim one pail contains only water, and the other has a piece of wood floating in it. Which pail has the greater weight?

Ans:

1) The pail without the piece of wood will have greater weight.

2) Wood in the second pail can float in water only if the weight of a volume of water displaced by it, is greater than the weight of wood.

v) Why does the fish float in the middle of the water?

Ans:

The swim bladder expands it will increase in volume and therefore displace more water. This increases the fish’s buoyancy and it will float upward.

vi), Why is atmospheric pressure greatest at the surface of Earth?

Ans:

The atmospheric air extends up to many kilometers above the surface of the earth. Atmospheric pressure varies with height at the surface of the Earth, atmospheric pressure is greatest because it has a maximum amount of air gases in form of different layers of atmosphere above the surface.

Unit-8: Force and Pressure: Solved Short Questions and Answers

Class 8 General Science Notes

Source: General Science Book (National Book Foundation, Pakistan)

************************************

Shortcut Links For:

1.  5th Class All Subjects Notes
2.  8th Class All Subjects Notes

1. Website for School and College Level Physics
(https://askrarequiz.blogspot.com)
2. Website for School and College Level Mathematics
(https://askraremaths.blogspot.com)
3. Website for Single National Curriculum Pakistan - All Subjects Notes
(https://askrareclassnotes.blogspot.com/)

© 2023 & onwards Academic Skills and Knowledge (ASK)

Note:  Write me in the comments box below for any query and also Share this information with your class-fellows and friends.