## Item RG081002: Kinetic energy is proportional to mass, so when a moving object has its mass increased by two the kinetic energy of that object increases by two.

A boy makes a small snowball and then pushes it around in the snow to make it bigger. He pushes it at a constant speed as the snowball gets bigger.

If the snowball doubles in mass, what will happen to the kinetic energy (motion energy) of the snowball?

1. The kinetic energy of the snowball will be less than what it was because even though the snowball is still moving at the same speed, the amount of kinetic energy it has decreases as it gets heavier.
2. The kinetic energy of the snowball will be double what it was because the amount of kinetic energy an object has is directly proportional to the mass of the object.
3. The kinetic energy of the snowball will be double what it was because the boy is now pushing harder and kinetic energy depends on the effort required to move an object.
4. The kinetic energy of the snowball will stay the same because the amount of kinetic energy an object has depends only on the speed of an object and not its mass.

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