A boulder is raised above the ground so that the gravitational potential energy relative to the ground is 360 J. Then it is dropped. What is its kinetic energy just before it hits the ground?
To determine the kinetic energy of the boulder just before it hits the ground, we can use the principle of conservation of mechanical energy. According to this principle, the total mechanical energy of an object in motion remains constant as long as no external forces, like air resistance, are acting on it.
Initially, the boulder possesses only gravitational potential energy. As it falls, this potential energy is converted into kinetic energy. Therefore, we can equate the initial gravitational potential energy to the final kinetic energy.
Given that the gravitational potential energy relative to the ground is 360 J, this is the value of the final kinetic energy just before the boulder hits the ground.
So, the kinetic energy of the boulder just before it hits the ground is 360 J.