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Gravitation
Two satellites of earth, S1 and S2 are moving in the same orbit. The mass of S1 is four times the mass of S2. Which one of the following statements is true ?
The time period of S1 is four times that of S2
The potential energies of earth and satellite in the two cases are equal
S1 and S2 are moving with the same speed
The kinetic energies of the two satellites are equal
C.
S1 and S2 are moving with the same speed
When two satellites of earth are moving in same orbit, then time period of both are equal.
From Kepler's third law
T2 ∝ r3
Time period is independent of mass, hence their time periods will be equal.
The potential energy and kinetic energy are mass dependent, hence the PE and KE of satellites are not equal.
But, if they are orbiting in a same orbit, then they have equal orbital speed.
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A solid sphere is rotating in free space. If the radius of the sphere is increased keeping mass same which one of the following will not be affected?
Which of the following statements is correct?
(a) Centre of the mass of a body always coincides with the centre of gravity of the body.
(b) Centre of the mass of a body is the point at which the total gravitational torque on the body is zero
(c) A couple on a body produce both translational and rotational motion in a body.
(d) Mechanical advantage greater than one means that small effort can be used to lift a large load.
Two astronauts are floating in gravitational free space after having lost contact with their spaceship. The two will:
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