Question

For each of the following processes, describe what kind of energy is being converted into what other kind(s). Valid forms of energy for the purpose of this question are “kinetic energy of (object),” “gravitational potential energy,” “elastic potential energy of (object),” or “internal energy of (object).” There may be more than one conversion involved, so your answer should be a kind of narration of the energy conversion(s).

For example, if the process is, “A girl skating on rollerblades skids to a halt,” then your answer should read something like: The kinetic energy of the girl is converted into internal energy of the skates and of the road.

You drop a book, and it falls to the floor and lands with a thud.

You drop a rubber ball, which hits the floor and rebounds back up to your hand. (Hint: Think about what happens to the ball while it is in contact with the floor.)

You pour milk from a carton into a drinking glass.

You pick up a heavy box from the floor and lift it onto a table.

You stretch a rubber band between your thumb and forefinger and release the rubber band. The rubber band shoots straight up into the air, falls back down, and lands motionless on the ground.

Answer 1

You drop a book, and it falls to the floor and lands with a thud.

The gravitational potential energy of the book converts into kinetic energy resulting in increasing speed, which on landing on ground converts to internal energy of floor and book

You drop a rubber ball, which hits the floor and rebounds back up to your hand. (Hint: Think about what happens to the ball while it is in contact with the floor.)

The gravitational potential energy of the ball converts to kinetic energy on losing height. Then it loses some energy as internal energy of floor and ball on hitting the ground. Finally the kinetic energy converts to potential energy, resulting in increasing height and rebounding back to hand

You pour milk from a carton into a drinking glass.

The gravitational potential energy of milk is converted to kinetic energy of milk as it fall which finally is converted to internal energy of milk and bowl.

You pick up a heavy box from the floor and lift it onto a table.

Your internal energy is converted to gravitational potential energy resulting in increase of height

You stretch a rubber band between your thumb and forefinger and release the rubber band. The rubber band shoots straight up into the air, falls back down, and lands motionless on the ground.

Your internal energy converts to elastic potential energy of the rubber band, which then converts to kinetic energy on being released. On falling the kinetic energy further increases at the expense of the gravitational potential energy. Finally on falling on ground, the kinetic energy is converted to internal energy of ground and rubber band.