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
Define calorific value of a fuel.
Write true or false of the following statement.
There is always some loss of energy in conversion from one form of energy to another form, so the total energy is not conserved.
A body of mass m falls down through a height h. Obtain an expression for the work done by the force of gravity.
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?
Name the energy changes for the following:
electric ball
What do you understand by mechanical energy?
What kind of energy is possessed in a situation when?
A stone, in a stretched catapult.
A body of mass m is taken from a height h to 2h. What is the increase in its potential energy?
Name the type of energy (kinetic energy K or potential energy U) possessed in the following case:
A moving cricket ball
Name the type of energy (kinetic energy K or potential energy U) possessed in the following case:
A moving bus
