If gravitational constant is decreasing with time, what will remain unchanged in case of a satellite orbiting around the earth?
A.
Time period
B.
Orbiting radius
C.
Areal velocity
D.
Angular velocity
Answer: Option C
Explanation:
The central gravitational force decreases which does not exert any torque. Hence the angular momentum and consequently areal velocity remain unchanged.
An elephant and an ant are to be projected out of the earth into space. What is the velocity needed to do so?
A.
Elephant needs to be projected with a higher velocity
B.
Ant should be projected with a higher velocity
C.
Both should be projected with the same velocity
D.
Elephant cannot be projected to space
Answer: Option C
Explanation:
The escape velocity ve=√2gR, does not depend upon the mass of the projected body. Thus we need the same velocity to project an elephant and an ant into space.