SPM Gravitation and circular motion

Which of the following statements explain Newtons Universal Law of Gravitation？

I. The gravitational force is inversely proportional to the square of distance between the centre of two bodies.

II. The gravitational fore can be attractive force or repulsive force.

III. The gravitational force is directly proportional to the product of the masses of the two bodies.

• I AND II

• I AND III

• II AND III

• I,II AND III

• 1.2m

• 1.5m

• 2.1m

• 2.5m

• 19.63N

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The diagram shows a simple pendulum of mass m revolves around a horizontal circle. Its centripetal force represented by

The diagram shows an object attached to the end of a string whirled round a circle with a speed of 15 ms^-1. If the mass of the object is 2 kg and the length of the string is 0.80 m, what is the tension of the string?

• 37.5N

• 75.4N

• 112.5N

• 562.5N

• 0.67

• 1.48

• 1.50

• 2.08

A satellite of mass m moves in a circular orbit a speed v and distance r from the centre of a planet of mass M. Which expression gives the total energy of the satellite?

Assume that the Earth is uniform sphere with radius R. Which graph shows the relationship between the gravitational force ,F and the distance x from the centre of the Earth?

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A satellite that revolves around the Earth can maintain its orbit without escaping to outer space because

• it is experiencing weightlessness

• it is moving in a vacuum

• it is always moving at very high speed

• it is always pulled by the gravitational force of the Earth