Energy Science Test

Describe six different forms of energy.

Mechanical energy is energy associated with motion and position. Thermal energy is the total potential and kinetic energy of the particles in an object. Chemical energy is energy stored in chemical bonds that hold compounds together. Electrical energy is energy associated with moving charges, or electric current. Electromagnetic energy is the energy of radiation, including visible light and microwaves. Nuclear energy is stored in the nucleus of an atom.

Compare the sum of the kinetic and potential energies of the pendulum at position A to the sum at position C. (Ignore friction.)

Point A is a point of maximum potential energy and minimum kinetic energy. Point C is the point of maximum kinetic energy and minimum potential energy. According to the law of conservation of energy, the sum of the kinetic and potential energies of the pendulum is constant, assuming no losses from friction. So the potential energy at A is equal to the kinetic energy at C.

How high must you lift a 25-newton book for it to have the same increase in potential energy as a 20-newton book that was lifted 0.5 m?

The increase in gravitational potential energy of the 20-newton book is 10 J (20 N • 0.5 m = 10 J). The 25-newton book must be lifted to a height of 0.4 m to have an increase in gravitational potential energy of 10 J (25 N • 0.4 m = 10 J).

Describe the energy of a bowling ball as it rolls toward and hits a bowling pin.

Answers may vary. As the ball rolls, it has some energy. In other words, it has the ability to do work and move the pin some distance. When it hits the bowling pin, it does work on the pin. During this process, some energy is transferred from the ball to the pin. After hitting the pin, the bowling ball has less energy than before, so it slows down.