“Exercise”
Choose the correct Answers.
1.Two masses are separated by a distance r . If both masses are doubled, the force of attraction between them changes by a factor of
a) 2
b)4
c) 1/2
d)1/4
Answer : (b)
2. The radius of earth Re is
a) 9.8 m
b) 6.67 ×10-11 m
c) 6×10²⁴ m
d) 6.4×10⁶ m
Answer: (d)
3.The S.I. unit for gravitational constant “G” is
a)N/kg²
b)Nm²/kg²
c)Nm²kg²
d) N/m²kg²
Answer: (b)
4.What is the mass on planet Mercury of an object that weighs 784 Newton on earth surface.
a)80.0kg
b) 118 kg
c) 784 kg
d) more information needed
Answer: (a)
5. An object is orbiting a planet with orbital speed v, if the radius is same and the mass is increased 4 times by what factor orbital speed will change
a) 2
b) 4
c) 1/2
d) 1/4
Answer: (a)
6. The value of g at the surface of moon is
a)9.8m/s²
b)1.63m/s²
c)4.9 m/s²
d)8.9m/s²
Answer: (b)
7. The value of g ……….. with altitude.
a) increase
b) decreases
c)gets zero
d) Remains the same
Answer: (b)
8. When a body is moved from sea level to the top of mountain, there is a change in Body’s
a) mass
b) weight
c) none
d) both mass and weight
Answer: (b)
9. The value of g at equator is…
a) same at poles
b) larger at poles
c) smaller at poles
d) none
Answer: (c)
