Case Study Based Questions: Force and Pressure | Science Class 8 PDF Download

Case Study

Read the given passage below and answer the question:

In a game of volleyball, players often push the moving ball to their team mates to make a winning move. Sometimes the ball is returned to the other side of the court by pushing or smashing it. In cricket, a batsman plays his or her shot by applying a force on the ball with the bat.

Q1: What kind of force is applied by a batsman on a ball while hitting it?
(a) Magnetic Force
(b) Muscular Force
(c) Frictional Force
(d) Gravitation Force
Ans: (b)
Explanation: While hitting a ball, the force is caused by the action of muscles in the batsman’s body. The force resulting due to the action of muscles is known as the muscular force.

Q2: Force can be defined as:
(a) Work done
(b) Energy required to do work
(c) Push or Pull
(d) Push only
Ans: (c)
Sol: A push or a pull on an object is called a force.

Q3: In the given example of a volleyball game, what changes force brought about on the volleyball?
(a) Change in direction of motion
(b) Change in shape
(c) Change in state of motion
(d) Both Option (a) and (c)
Ans: (d)
Sol: When players hit the volleyball, its speed changes and also the direction of its motion changes.

Q4: How do you describe the state of motion?
Ans: A change in either the speed of an object, or its direction of motion, or both, is described as a change in its state of motion. The state of rest is considered to be the state of zero speed. An object may be at rest or in motion; both are its states of motion.

Q5: Give two examples showing that force has brought about a change in the shape of an object.
Ans: 1. Pressing a ball of dough by a rolling pin to make chapati.
2. Stretching a rubber band.