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Physics: Gravitation

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1. A planet is moving around the Sun in a circular orbit of

circumference C. The work done on the planet by the gravitational

force F of the Sun is

FC/2 Zero. F/C FC


A reference frame attached to the Earth

cannot be an inertial frame of reference because of

the Earth's rotation and revolution.

is an inertial frame because Newton's laws of

motion are applicable inside it.

is not an inertial frame because the Earth moves

with respect to the Sun.

is an inertial frame by definition.


3. Two planets of radii R1 and R2 have the same density. The ratio of

their accelerations due to gravity at the surface is

(R2 /R1)2 (R1 /R2)2 R2 /R1 R1 /R2


4. A satellite is moving around the Earth in a circular orbit with a

velocity V. If the gravitational force of the Earth were to suddenly

disappear, then the satellite would

move radially outwards with a velocity V.

move with a velocity V, tangentially to its

circular orbit.

fall towards the surface of the Earth.

spirally move away from the Earth.


5. An Earth satellite of mass m revolves at a height h from the surface

of the Earth. If R is the Earth's radius and g is the acceleration due
to gravity at the surface of the Earth, then the velocity of the

satellite is given by

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