PHYSICS DEPARTMENT
PHY 2053
2nd Exam
Summer 2001
Useful information:
G
=6
.
67
×
10

11
N*m
2
/kg
2
Radius of the Earth:
R
=6
.
38
×
10
6
m
Mass of the Earth:
M
=5
.
98
×
10
24
kg
Moments of Inertia:
Hoop or cylindrical shell:
I
=
MR
2
Solid cylinder or disk:
I
=
1
2
MR
2
Solid sphere:
I
=
2
5
MR
2
Long thin rod about its center:
I
=
1
12
ML
2
Long thin rod about its end:
I
=
1
3
ML
2
1. An object at rest explodes into three pieces of equal mass. One moves East at 20 m/s; a second moves 45 degrees South
of East at 30 m/s. What is the velocity of the third piece?
(1) 46 m/s at 27 degrees North of West
(2) 78 m/s at 33 degrees West of North
(3) 22 m/s at 17 degrees South of West
(4) 35 m/s at 45 degrees North of West
(5) 58 m/s at 62 degrees North of East
2. A 1.2 kg ball drops vertically onto a ﬂoor, hitting with a speed of 25 m/s. It rebounds with an initial speed of 10 m/s.
If the ball is in contact with the ﬂoor for 0.02 s, what is the magnitude of the average force on the ﬂoor from the ball?
(1) 2100 N
(2) 900 N
(3) 18 N
(4) 100 N
(5) 1700 N
3. A 0.01 kg bullet is Fred into a 2.5 kg ballistic pendulum and becomes embedded in it. If the pendulum rises a vertical
distance of 0.08 m, calculate the initial speed of the bullet. Use
g
=9
.
80 m/s
2
.
(1) 315 m/s
(2) 1350 m/s
(3) 925 m/s
(4) 2 m/s
(5) 784 m/s
4. Two blocks of mass
m
1=2
.
0kgand
m
2=6
.
0kgsitonasemicircular
frictionless track of radius
R
=0
.
50 m. Initially, the block of mass
m
1
sits at rest at the bottom of the track, while the second block of mass
m
2ishe
ldfromahe
ight
R
and then released from rest. The collision
between the two blocks is perfectly inelastic. What is the maximum
height the blocks will reach after the collision? Use
g
=9
.
80 m/s
2
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 Fall '06
 Buchler
 Physics, Inertia, Kinetic Energy, Mass, General Relativity

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