Question

A ball falling through the air has ___________. (The ground is the zero reference point)

Question 19 options:

both potential and kinetic energy


only kinetic energy


only potential energy


neither potential energy nor kinetic energy


only thermal energy

Question 20 (1 point)
When a fast moving car brakes to a stop, the brakes heat up because of friction. This is an example of _____________.

Question 20 options:

one form of energy being converted to another form


energy being created


energy being destroyed


periodic motion


elastic motion

Answer 1

19. Both potential and kinetic.

20. One form of energy (kinetic) being converted to another form (heat).

Answer 2

19. Answer;

both potential and kinetic energy

Explanation;

• A ball falling through the air has both potential and kinetic energy. A ball falling through the air has several forms of energy.
• When the ball is falling it means it is in motion, thus it posses kinetic energy, which is the energy that causes motion. The ball also posses potential energy, as when the body is falling, potential energy is converted to kinetic energy until the ball achieves maximum kinetic energy when the velocity is maximum, then when it falls on the ground and rests, it eventually ends up with maximum potential energy.
• Therefore, a ball falling through air has potential energy because still has a distance before it hits the ground and kinetic energy because it is moving.

20. Answer;

-one form of energy being converted to another form

Explanation;

• According to the Law of conservation of energy, energy cannot be created or destroyed but can be changed from one form to another. example: when a car stops; the brakes heat up because of friction, thus the energy changes from one form to another.

• The kinetic energy of the moving car is converted to heat energy in the braking system.