Physics 111
Exam 3
Name (please print)
_____________________________________
A
1.
A 3 kg steel ball falls down vertically and strikes a floor with a speed of 12 m/s.
It bounces off upward with the same speed.
If the
ball is in contact with the floor for 0.12 s,
what is the magnitude of the average force exerted on the ball by the floor?
A)
200 N
B)
400N
C)
600 N
D)
800 N
E
1000 N
2.
A baseball player uses a pitching machine to help him improve his batting average.
He places the 60kg machine on a frozen
pond.
The machine fires a 0.12kg baseball horizontally at a speed of 36 m/s.
What is the magnitude of the recoil velocity of the
machine?
A)
3.6 cm/s
B)
7.2 cm/s
C)
10.4 cm/s
D)
15.2 cm/s
E)
36 cm/s
3.
The turntable of a record player rotates at a rate of 18 rev/min.
It takes 70 seconds for the turntable to come to rest when switched
off.
Calculate the magnitude of its angular acceleration.
A)
0.012 rad/s
2
B)
0.027 rad/s
2
C)
0.054
rad/s
2
D)
0.108
rad/s
2
E)
0.216
rad/s
2
4.
The turntable of a record player rotates at a rate of 18 rev/min.
It takes 70 seconds for the turntable to come to rest when switched
off.
Calculate the number of revolutions it makes before coming to rest.
A)
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 Spring '08
 moro
 Physics, Angular Momentum, Moment Of Inertia, Rigid Body, Rotation

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