2. Focus during the entire Power Point activity.
Solidify your studying skills during this
class period.
Perform your work in your science journal so
you have created a study guide for the test.
Call me over if you are having difficulty
getting started.
If your answer is confirmed as correct,
become a student/teacher and help someone
in class who does not understand the
method used to solve the problem.

3. Know Definitions of Key
Terms & Symbols

4. The Batallac, the 1500 kg car used by
Batfink and Karate to fight crime, is
stopped at a height of 35 meters at the top
of a damaged bridge. You may assume
there is no friction. How much energy
has been transferred? What container is
this energy stored in? Remember that
Batfink is 50 kg and Karate is 150 kg.

5. SOLUTION:
How much energy has been transferred into
which container?
K
U
m = 1700 kg
g = 9.8 m/s2
Δy = 35 m
Ug
Ug = 583,100 J
F = -kΔl
P = W/t

6. What is the velocity of
the Batallac just before
it hits the water?

7. SOLUTION:
Final velocity.
K
U
m = 1700 kg
mb = 25 kg
Δy = 35 m
Ug = 583,100 J
Vf
Vf= 26.19 m/s
F = -kΔl
P = W/t

8. Our heroes, Batfink and Karate, are
stuck in quick drying cement. Big
Ears Ernie has vertically displaced a
one metric ton (1,000 kg) wrecking
ball 4 meters and is attempting to
smash them. How much energy is
being stored in the g-field?

9. SOLUTION:
Find energy.
K
U
m = 1000 kg
Δy = 4 m
g = 9.8 m/s2
Ug
Ug= 39,200 J

10. Draw an energy bar chart to
illustrate the distribution of
energy when the wrecking
ball is displaced 3 meters at
the opposite end of it’s swing.

11. SOLUTION:
Distribution of energy containers.
K
ET = 39,299 J
m = 1000 kg
Δy = 3 m
g = 9.8 m/s2
U
KE
KE= 9,800 J

12. 45,000
40,000
35,000
30,000
25,000
20,000
15,000
10,000
5,000
0
Total Energy
Ug
KE

13. What was the force exerted
on the wrecking ball to
place it in its original
position?

14. SOLUTION:
Find force.
K
U
m = 1000 kg
Δy = 4 m
g = 9.8 m/s2
F
F= 9,800 N

15. The Batallac has come to a
stop between the two bridge
decks 81.87 meters above the
icy river. What is the total
energy in the gravitational
field?

16. SOLUTION:
Find energy.
K
U
m = 1700 kg
Δy = 81.87 m
g = 9.8 m/s2
Ug
Ug= 1,363,954.2 J

17. What is the maximum
velocity the batallac will
attain before hitting the
water?

18. SOLUTION:
Find velocity.
K
U
m = 1700 kg
v
Δy = 81.87 m
g = 9.8 m/s2
Ug= 1,363,954.2 J
v = 40.06 m/s

19. How much time would it
take for the batallac to
reach the water below?

20. SOLUTION:
Find time.
K
U
vi = 0 m/s
vf = 40.06 m/s
Δy = 81.87 m
g = 9.8 m/s2
tf
tf= 4.09 s

21. Fortunately, Batfink is able to
free himself from the Batallac
and stop the car from falling
into the river. How much
force was needed to bring the
car to a complete stop?

22. SOLUTION:
Find force.
K
U
m = 1700 kg
F
Δy = -81.87 m
g = 9.8 m/s2
Ug= 1,363,954.2 J
F = -16,660 N

23. If this force was applied
during the entire fall of
the Batallac, how much
power did Batfink
exert?

24. SOLUTION:
Find power.
K
U
m = 1700 kg
P
Δy = 81.87 m
g = 9.8 m/s2
Ug= 1,363,954.2 J
Tf = 4.09 s
P = 333,485.13 W

25. Batfink is dropped
through a trap door
disguised as a welcome
mat. If he falls 20
meters, what is his KE
just before hitting the
ground?

26. SOLUTION:
Find energy.
K
U
m = 50 kg
Δy = -20 m
g = 9.8 m/s2
KE
KE = -9,800 J

27. Fortunately for Batfink, there
was a spring on the floor
under the trap door. If the
force needed to compress
this spring 3 meters is 2100
N, what is the spring
constant?

28. SOLUTION:
Find spring constant.
K
U
F = 2100 N
Δl = 3 m
k
k = 700 N/m

29. How far did the spring
compress if all the
energy from Batfink was
transferred to the
spring?

30. SOLUTION:
Find change in length.
K
U
Us = 9,800 J
k = 700 N/m
Δl
Δl = 5.29 m