Advertisements
Advertisements
प्रश्न
A ball of mass 50 g falls from a height of 2m and rebounds from the ground to 1.6 m. Find:
(i) The potential energy possessed by the ball when initially at rest.
(ii) The kinetic energy of the ball before it hits the ground.
(iii) The final potential energy of the ball.
(iv) The loss in kinetic energy of the ball on collision. (Take: g = 10N kg−1)
Advertisements
उत्तर
Given : m = 50g = `50/1000`kg = 0.05 kg,
g = 10N kg−1,
h1 = 2m = 1.6 m.
(i) Initial potential energy possessed by the ball = mgh1
= 0.05 × 10 × 2 = 1.0 J.
(ii) The K.E. of the ball before it hits the ground
= Initial potential energy possessed by the ball
= 0.1 J
(iii) The final potential energy of the ball = mgh2
= 0.05 × 10 × 1.6
= 0.8 J.
(iv) The kinetic energy of the ball after striking the ground
= Final potential energy of the ball = 0.8 J
संबंधित प्रश्न
Write true or false of the following statement.
The energy of flowing water can be converted into electric energy (electricity).
Name the type of energy (kinetic or potential) possessed by the following:
A compressed spring.
A boy of mass m climbs up a staircase of vertical height h.
(a) What is the work done by the boy against the force of gravity?
(b) What would have been the work done if he uses a lift in climbing the same vertical height?
Select the renewable and non-renewable sources of energy from the following:
Diesel
State two disadvantages of producing electricity from solar energy.
State the energy changes which take place when:
In a heat engine.
State the energy changes which take place when:
An air gun is loaded and then fired.
In which states is water found in nature?
Unit of calorific value of a substance is ____________.
