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P211 Final Sample 1
9) If a 0.2 kg ball is dropped from rest from a height of 2 m above the floor, it rebounds only up to
1.5 m, because the collision with the floor is not perfectly elastic and some energy is lost. What is
the magnitude of the impulse, or momentum change, imparted on the ball by the collision with the
floor? (Hint: find the magnitude and direction of the momentum just before, and just after, the
collision with the floor.)
A) 0.168 kg m/s B) 2.34 kg m/s C) 4.03 kg m/s
D) 7.23 kg m/s E) 11.7 kg m/s
10) You are sitting still in a room taking a Phys 211 exam. What is the magnitude of your linear
velocity due to the Earth’s rotation? The Earth has a rotation period of 23.93 hours, is approximately
a sphere of mean radius R E = 6371 km, and State College is at a latitude of θ = 40.8º North, as
shown in the figure. (Hint: what is the radius R SC of the circular motion of State College around the
Earth’s axis of rotation?)
A) 352 m/s (787 mph)
B) 465 m/s (1040 mph)
C) 2830 m/s (6331 mph)
R SC
R E
State College
D) 5320 m/s (11901 mph)
θ
E) 9.8 m/s (21.9 mph)
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