Energy problem 35

Which of the following statements are correct:

  • As a body falls, its kinetic and potential energies remain unchanged.

  • A plasticine falls to the ground and stops without bouncing. The potential energy before the fall is equal to the internal energy when it stops on the ground.

  • A parachutist falls evenly towards the ground. The potential energy of the parachute is converted into the internal energy of the parachute and the surrounding air during the fall.

  • An athlete throws a spear with the force of his body. After 50 m of flight, the spear sinks into the ground. The law of conservation of energy applies from the moment the athlete picks up the spear.

  • A pendulum oscillates from one extreme position to another. The total energy of the pendulum is equal to its kinetic energy at its lowest, i.e., equilibrium position.

  • A car accelerating up a hill applies the law of conservation of energy.


material editor: Habeeb Adenle