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PHY 131 Midterm 2
Apr 7, 2008
Version
Put FULL NAME, ID#, and EXAM VERSION on the front cover of the BLUE BOOKLET!
Do all problems and write and mark legibly
! Use your blue booklet for your calculations and mark your answers
by circling the appropriate answer on this sheet. Use pencil and eraser; when modifying your answer make it
VERY clear what your modification is, or get a new sheet. This exam will last 50 minutes. Success!
1.
Conservation Laws (24 points).
List the Conservation Laws needed to solve the problems listed below. Do
NOT solve the problems, just list the Conservation Laws that apply to the problem’s situation!
Problem
(3 points max., 0 points min. per problem)
Δ
p
=0
Δ
L
=0
Δ
K
=0
Δ
E
=0
W
NC
=
Δ
E
a.
A projectile is shot from a vertical cliff above the sea (
v
0
, height
h
);
calculate the maximum height and the speed just before impact. Ig
nore drag.
1
(2)
2
(2)
3
(2)
4
(+3)
5
(+3)
b.
A uniform cylinder (
R
,
m
) rolls from rest down an incline (length
D
,
height
h
; friction
μ
k
); what is its final speed?
1
(2)
2
(2)
3
(2)
4
(1)
5
(+3)
c.
Two sliders (
m
1
,
v
1
,
m
2
,
v
2
) on a horizontal frictionless air track col
lide elastically; what are the final velocities?
1
(+2)
2
(0)
3
(+2)
4
(+1)
5
(1)
d.
A merrygoround (
R
,
I
,
ω
i
>0). A boy (
m
) plops down on the rim (he
has
ω
0
=0). What is the
ω
f
of merrygoround plus boy?
1
(0)
2
(+3)
3
(2)
4
(2)
5
(0)
e.
A bug (
m
) slides off a round frictionless spherical dome (
R
), starting
at rest from the top; where does it have enough speed to leave the sur
face?
1
(2)
2
(2)
3
(2)
4
(+3)
5
(0)
f.
A satellite (
m
) is launched into orbit around Earth (altitude
h
); what is
the energy needed to bring it into orbit?
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 Spring '03
 Rijssenbeek
 Angular Momentum, Force, Rotation, vector sum, rotation axis

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