8
MCQ (Single Correct Answer)
Particles of masses $$2 M, m$$ and $$M$$ are respectively at points $$A, B$$ and $$C$$ with $$A B=\frac{1}{2}(B C) \cdot m$$ is much-much smaller than $$M$$ and at time $$t=0$$, they are all at rest as given in figure. At subsequent times before any collision takes place.
A
m will remain at rest
B
m will move towards M
C
m will move towards 2M
D
m will have oscillatory motion
9
MCQ (Multiple Correct Answer)
Which of the following options are correct?
A
Acceleration due to gravity decreases with increasing altitude
B
Acceleration due to gravity increases with increasing depth (assume the earth to be a sphere of uniform density)
C
Acceleration due to gravity increases with increasing latitude
D
Acceleration due to gravity is independent of the mass of the earth
10
MCQ (Multiple Correct Answer)
If the law of gravitation, instead of being inverse square law, becomes an inverse cube law
A
planets will not have elliptic orbits
B
circular orbits of planets is not possible
C
projectile motion of a stone thrown by hand on the surface of the earth will be approximately parabolic
D
there will be no gravitational force inside a spherical shell of uniform density
11
MCQ (Multiple Correct Answer)
If the mass of the sun were ten times smaller and gravitational constant $$G$$ were ten times larger in magnitude. Then,
A
walking on ground would become more difficult
B
the acceleration due to gravity on the earth will not change
C
raindrops will fall much faster
D
airplanes will have to travel much faster
12
MCQ (Multiple Correct Answer)
If the sun and the planets carried huge amounts of opposite charges,
A
all three of Kepler's laws would still be valid
B
only the third law will be valid
C
the second law will not change
D
the first law will still be valid