Physics 218 Honors; Secs. 201,202,203; Exam 3, Fall-lO
Name:
Section. No:
NOTE: Each problem is worth 20 pts
0 rolls on the inside of a track of radius R. If the ball starts from rest at the vertical
1. A ball of radius r
edge of the track, what will be its speed when it reaches the lowest point of the track, rolling without
slipping? Express your answer in terms of r
, R, and g. NOTE: For a sphere, ‘CM = 2Mr
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2. A thin uniform stick of mass M and length L is positioned vertically with its tip on a frictionless
table. It is released and allowed to fall. Determine the speed of its CM just before it hits the table.
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3. A thin rod of mass M and length L rests on a frictionless table and is struck at a point L14 from its CM by a
lump of dough of mass m moving at speed V. The dough sticks to the rod. (Note: for rod ‘CM = ML
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a) Find the CM of the system of rod and dough relative to the CM of the rod.
b) What is the moment of inertia of the rod about this new CM?
c) Determine the velocity of the new CM in terms of V, m, and M
b) Determine the angular velocity of the rod about the new CM in terms of V, m, M, and L.
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5. A NASA satellite has just observed an asteroid that is on a collision course with the Earth. The
asteroid has an estimated mass of of 5 x 1 ü kg. It is approaching the earth on a head-on course with a
velocity of 660 mIs relative to the Earth and is now 5.0 x 106 km away. With what speed will it hit the
Earth’s surface, neglecting friction with the atmosphere? NOTE: mass of Earth = 5.98 x 1024 kg, and
radius of Earth = 6.38 x 106 m, G = 6.67 x 10h1 2
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