4
MCQ (Single Correct Answer)
Satellites orbitting the earth have finite life and sometimes debris of satellites fall to the earth. This is because
A
the solar cells and batteries in satellites run out
B
the laws of gravitation predict a trajectory spiralling inwards
C
of viscous forces causing the speed of satellite and hence height to gradually decrease
D
of collisions with other satellites
5
MCQ (Single Correct Answer)
Both the earth and the moon are subject to the gravitational force of the sun. As observed from the sun, the orbit of the moon
A
will be elliptical
B
will not be strictly elliptical because the total gravitational force on it is not central
C
is not elliptical but will necessarily be a closed curve
D
deviates considerably from being elliptical due to influence of planets other than the earth
6
MCQ (Single Correct Answer)
In our solar system, the inter-planetary region has chunks of matter (much smaller in size compared to planets) called asteroids. They
A
will not move around the sun, since they have very small masses compared to the sun
B
will move in an irregular way because of their small masses and will drift away into outer space
C
will move around the sun in closed orbits but not obey Kepler's laws
D
will move in orbits like planets and obey Kepler's laws
7
MCQ (Single Correct Answer)
Choose the wrong option.
A
Inertial mass is a measure of difficulty of accelerating a body by an external force whereas the gravitational mass is relevant in determining the gravitational force on it by an external mass
B
That the gravitational mass and inertial mass are equal is an experimental result
C
That the acceleration due to gravity on the earth is the same for all bodies is due to the equality of gravitational mass and inertial mass
D
Gravitational mass of a particle like proton can depend on the presence of neighbouring heavy objects but the inertial mass cannot
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