Question

Q1. Assertion - We donot work as we push a wall
Reason - The condition for the force to do work is that it should produce motion in object.
Q2. Assertion Stretched bow has potential energy.
Reason - Catapult has kinetic energy.
Q3. Assertion -- A ball rebound to the same height on striking the ground, from which it was released.
Reason - According to the law of conservation of energy, the total energy of the system remains same.
Q4. Assertion - Work done by athlete completing a round of a field is Zero
Reason - The displacement of body returning back to the initial positon is ze o
Q5.Assertion - There is no need to save fuel since the total of the universe is constant.
Reason: the resources available on earth are limited and once used they are converted into non-
reusable forms of energy.

Answer 1

Answer:

1- a is false and r is false

2- a is true r is false

3- both a and r are true but r is not correct explanation of a

4-a and r are true and r is correct explanation

5-a is false and r is true

Explanation: