EASY
9th CBSE
IMPORTANT
Earn 100

The potential energy of a freely falling object decreases progressively. Does this violate the law of conservation of energy? Why?

Important Questions on Work and Energy

EASY
9th CBSE
IMPORTANT

State the transformation of energy when: Green plants prepare food-

EASY
9th CBSE
IMPORTANT
State the transformation of energy when: Head of a nail is hammered hard and it becomes hot.
EASY
9th CBSE
IMPORTANT
Derive an expression for gravitational potential energy.
EASY
9th CBSE
IMPORTANT

A skier of mass 50 kg stands at 'A' at the top of a ski jump. He takes off at 'A' for his jump to 'B'. Calculate the change in his gravitational potential energy between 'A' and 'B'.

MEDIUM
9th CBSE
IMPORTANT
The velocity of a body moving in a straight line is increased by applying a constant horizontal force F, for some distance in the direction of motion. Prove that the increase in kinetic energy of the body is equal to the work done by the force.
MEDIUM
9th CBSE
IMPORTANT
Show that the total mechanical energy remains conserved during the free fall motion of a stone.
MEDIUM
9th CBSE
IMPORTANT
Derive an expression for kinetic energy of a body.
EASY
9th CBSE
IMPORTANT
A man weighing 60 kg goes up a staircase 5 m high in 20 s. What is his power? (g: 9.8 ms2)