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# Tag Archives: satellite

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## Class XI CBSE – Revision Questions MCQ – Semester 1

1. What is the gravitational field strength of a planet when the weight of a 100 kg astronaut is 400 N?

a)      ¼ N kg-1   b) 9.8 N kg-1 c) 4 N kg-1  d) infinity

1. The only natural satellite of the earth complete orbits in about

a)      24 days b) 27.3 days c) 30 days d) 365 1/4 days

1. The satellite that revolves in a polar orbit is called

a) Natural Satellite b) Geostationary satellite   c) Polar Satellite   d) None of these

4)  The height of a communication satellite above the earth’s surface is about

a) 1km b) 100 Km    c) 10,000 Km    D) 36000 Km

5) At what depth below the earth’s surface does the weight of  a body  becomes 1% of its value at the surface of the earth?

a) 32Km  b) 64 Km   c) 128 Km   d) 164 Km

6) The arte of change of angular momentum is called

a) a Force  b) Torque  c) Impulse  d) None of these

7) Which of the following has the largest moment of inertia (Each object has same mass)

a) Solid sphere

b) Bar Magnet

c) Ring about an axis perpendicular to its plane

d) Disc about an axis perpendicular to its plane

8) A hollow cylinder and a solid cylinder having same mass and same diameter are related simultaneously from rest from the top of the inclined plane. Which of them will reach the bottom first?

a) Solid cylinder

b) Hollow Cylinder

c) Both will reach the bottom together

d) One having greater density

9) A body moving with a constant speed on a horizontal surface does not have

a) Velocity

b) Momentum

c) Kinetic Energy

d) Acceleration

10) Which of the following has its unit as Newton-Second

a) Torque b) Momentum   c) Energy   d) Planck is constant

FIND MORE HERE http://www.scribd.com/doc/7067782/MCQ-on-Basic-Physics

## Why gravitational force of attraction is necessary for a satellite to revolve around earth?

The question was posted by Raj Kumar.

The satellite has a velocity. To revolve around, the direction of velocity must change. In the absence of a force it can move only in a straight line. It is the gravitational force which helps the satellite top change direction and revolve around the earth.

In other words, for a satellite to revolve in a circular path, a centripetal force is required. This centripetal force is provided by the force of gravitation only.

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