Question

1. which has kinetic energy?

a) a tank of gasoline
b) a moving car
c) a battery
d) water in a reservoir

1. which type of energy does an object not have if it is not moving?

a) kinetic energy
b) gravitational potential energy
c) elastic potential energy
d) chemical potential energy

1. which indicates what happens to the kinetic energy when the mass of a moving object increases?

a) the kinetic energy does not change.
b) the kinetic energy increases by the same factor as the mass increase.
c) the kinetic energy increases by the square of the same factor as the mass increase.
d) the kinetic energy decreases by the same factor as the mass increase.

1. which indicates what happens to the kinetic energy of an object when its speed increases?

a) the kinetic energy does not change.
b) the kinetic energy increases by the same factor as the speed increase.
c) the kinetic energy increases by the square of the same factor as the speed increase.
d) the kinetic energy decreases by the same factor as the speed increase.

Explanation:

Question 6

Kinetic energy is the energy of motion. A moving car is in motion, so it has kinetic energy. A tank of gasoline (chemical potential energy), a battery (chemical potential energy), and water in a reservoir (potential energy if at height) are not in motion for kinetic energy.

Kinetic energy depends on motion ($KE = \frac{1}{2}mv^2$). If an object is not moving, $v = 0$, so it has no kinetic energy. Gravitational, elastic, and chemical potential energies don't require motion.

The formula for kinetic energy is $KE=\frac{1}{2}mv^2$. If mass $m$ increases by a factor (say $k$), new $KE'=\frac{1}{2}(km)v^2 = k(\frac{1}{2}mv^2)=kKE$. So KE increases by the same factor as mass.

Answer:

B) a moving car

Question 7