# Orbit and Radius Drum Rotates

1. A 1400 kg car is travelling at 25 m/s on a circular hill of radius 210 m. What is the normal force on this car at the top of the hill? [pic]

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2. In an amusement park, a 2.8 m radius “drum” rotates such that a person does not fall when the “floor” drops away. [pic]

If the coefficient of friction between the person and the wall is 0.35, what is the maximum period of the rotation so that a person will not fall? A. 2.0 s

B. 3.4 s

C. 5.7 s

D. 18 s

3. Which of the following is a correct statement about gravitational force? A. It is applicable only to our solar system.

B. It is both an attractive and repulsive force.

C. It is directly proportional to the product of the masses involved. D. It is directly proportional to both the mass and radius of the earth.

4. The net force acting on a body in uniform circular motion is constant in A. direction only.

B. magnitude only.

C. both magnitude and direction.

D. neither magnitude nor direction.

5. A 1200 kg car travels with a maximum speed of 24 m/s in a circular path on a dry level road surface where the coefficient of friction = 0.90 between the car tires and the road. What is the radius of this circular path? A. 27 m

B. 59 m

C. 65 m

D. 640 m

6. Two satellites, S1 and S2, are in circular orbits around a planet. Satellite S2 has twice the mass and twice the orbital radius of satellite S1.

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What is the ratio of the centripetal force on S2 to that of S1 (S2 : S1) ? A. 1:1

B. 1:2

C. 1:4

D. 1:8

7. Which of the following is a correct statement about gravity? A. An object falling freely has no gravitational force on it. B. The acceleration due to gravity, g, is a universal constant. C. The gravitational field of a body follows an inverse square law. D. The gravitational potential energy varies with the square of distance of separation.

8. The mass of planet Neptune is 17 times more than that of the earth. It has a radius 3.8 times...

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