Energy and Its Conservation
Practice Test
1.
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.
-3.7×10
4
J
d.
1.8×10
4
J
Hint
2.
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.
1.8×10
4
J
b.
-5.5×10
4
J
c.
3.7×10
4
J
d.
-3.7×10
4
J
Hint
3.
In Figure 11-5, estimate the vertical velocity of an orange when it hits the juggler's left hand.
a.
2 m/s
b.
0.45 m/s
c.
4.5 m/s
d.
20 m/s
Hint
4.
A collision in which kinetic energy decreases is called a(n) __________.
a.
energy conservation
b.
elastic collision
c.
mechanical collision
d.
inelastic collision
Hint
