Answers to Circular Motion/Gravitation Review Problems:1.The speed can be found from the centripetal force and centripetal acceleration.

2. To find the period, the rotational speed (in rev/min) is reciprocated to have min/rev, and then

converted to sec/rev. Use the period to find the speed, and then the centripetal acceleration.

3. The centripetal force that the tension provides is given by . Solve that for the speed.

4. The spacecraft is three times as far from the Earths center as when at the surface of the Earth. Therefore, since the force as gravity decreases as the square of the distance, the force of gravity on the spacecraft will be one-ninth of its weight at the Earths surface.

This could also have been found using Newtons law of Universal Gravitation.

5. (a)Mass is independent of location and so the mass of the ball is 21.0 kg on both the Earth and the

planet.

(b)The weight is found by .

.

6. Assume that the two objects can be treated as point masses, with and . The gravitational force between the two masses is given by

.

This can be rearranged into a quadratic form of . Use the quadratic formula to solve for m, resulting in two values which are the two masses.

.

_1142242060.unknown

_1142250502.unknown

_1142250514.unknown

_1142250720.unknown

_1142250747.unknown

_1142250709.unknown

_1142250508.unknown

_1142250485.unknown

_1142242024.unknown

_1142242054.unknown

_1105209633.unknown

_1142241874.unknown

_1105209631.unknown