# Physical Science

Work is the rate at which you expend energy.

True
False

The energy an object has because of its motion is called potential energy.
True
False

Plants convert radiant energy from the sun into chemical energy by a process called photosynthesis.
True
False
Ignoring air resistance, an object that falls twice as far will be moving twice as fast when it hits the ground.
True
False

Nearly all of the energy consumed today is provided by petroleum, coal, hydropower and nuclear sources.
True
False

The joule (J) is a unit of
work.
weight.
power.
force.

The quantity that has units is known as a
joule.
newton.
horsepower.
watt.

Which one of the following does not have the same units as the others?
kinetic energy
momentum
potential energy
work

A car traveling 20 mph can stop in about 40 ft. If the same car was traveling twice as fast, its stopping distance would be roughly
40 ft.
60 ft.
80 ft.
160 ft.

Kinetic energy refers to
energy of motion.
energy of position.
energy stored in fossil fuels.
electrical energy.

The amount of energy produced by power-generating dams is

increasing, as more of this clean, non-polluting resource is used.
increasing, as more renewable resources are used.
decreasing, as old dams are destroyed for environmental reasons.
decreasing, as more energy is used but new dams are not being built.

The potential energy of a ball on the ground is zero. If the ball is then placed in the bottom of a hole, its potential energy will be

nonexistent.
the same as it was on the surface.
negative.
zero.

While exploring an ancient Mayan tomb, you discover that the walls are closing in on you. By exerting 400 N of force, you are able to keep the walls from coming anycloser. The work you are then doing on the wall is
400 J.
3920 J.
unknown, because the mass of the wall is not given.
zero, because the wall is not moving.

Roughly, what fraction of our nation’s current energy needs is supplied by coal?
10%
20%
40%
80%

You can find the kinetic energy of a book of a known mass just before it hits the floor after falling a known distance by using which equation?

W = Fd
K.E. = ½ mv2
P.E. = mgh
None of these.