Chapter 11:
Energy
Practice Test
1.
If no other forms of energy besides kinetic and gravitational potential energy are present, then mechanical energy is represented by the equation __________.
a.
U
g
= mgh
b.
M
E
= 1/2 KU
g
2
c.
U
g
= E + K
d.
E
=
K
+
U
g
Hint
2.
In an accident on a slippery road, a car with mass 800.0 kg, moving at 12.0 m/s, smashes into the rear end of a car with mass 1250 kg moving at 8.00 m/s in the same direction. How much kinetic energy was lost in the collision if the wrecked cars lock together?
a.
3.9 × 10
4
J
b.
4.1 × 10
4
J
c.
6.1 × 10
4
J
d.
3.9 × 10
3
J
Hint
3.
A 75-kg rock climber first climbs 25 m to the top of a quarry, then descends 75 m from the top to the bottom of the quarry. If the initial height is the reference level, what is the potential energy of the system (climber plus Earth) at the top?
a.
1.8 × 10
4
J
b.
-3.7 × 10
4
J
c.
-1.8 × 10
4
J
d.
3.7 × 10
4
J
Hint
4.
A large chunk of ice with mass 12.0 kg falls from a roof 6.00 m above the ground. Ignoring air resistance, what is the kinetic energy of the ice when it reaches the ground?
a.
7.06 × 10
3
J
b.
-7.06 × 10
3
J
c.
7.06 × 10
2
J
d.
-7.06 × 10
2
J
Hint
5.
The sum of the kinetic and gravitational potential energies of a system is called __________.
a.
reference energy
b.
momentum
c.
mechanical energy
d.
conserved energy
Hint
6.
The energy of motion of an object is __________ energy.
a.
latent
b.
kinetic
c.
potential
d.
elastic
Hint
7.
If work is done on an object, the energy of the object __________.
a.
is unaffected, but its acceleration changes
b.
decreases by an amount equal to the work done
c.
increases by an amount equal to the work done
d.
is equal to the work done
Hint
8.
Stored energy that is a result of the gravitational interaction between an object and Earth is __________.
a.
gravitational potential energy
b.
mechanical energy
c.
the reference level
d.
elastic potential energy
Hint
9.
A steel ball with mass 5.0 kg is at rest on a smooth, level surface. A constant force acts on it through a distance of 10.0 m causing it to roll at 25 m/s. What is the magnitude of the force?
a.
6.3 N
b.
4.9 N
c.
1.6 × 10
2
N
d.
1.6 × 10
3
N
Hint
10.
A 75-kg rock climber first climbs 25 m to the top of a quarry, then descends 75 m from the top to the bottom of the quarry. If the initial height is the reference level, what is the potential energy at the bottom?
a.
-3.7 × 10
4
J
b.
-5.5 × 10
4
J
c.
1.8 × 10
4
J
d.
3.7 × 10
4
J
Hint
