1. What happens to the gravitational force between two objects if the distance between them triples?
A. The force increases by a factor of 3
B. The force decreases by a factor of 9
C. The force increases by a factor of 9
D. The force decreases by a factor of 3
2. By what factor does the gravitational force between two objects increase if one object doubles in mass and the distance between them decreases by half?
A. 4
B. 2
C. 8
D. 1
3. What must be the units for the gravitational constant G in order for gravitational force to have units of newtons?
A. m3/(kg2⋅s2)
B. m3/(kg⋅s)
C. m3/(kg⋅s2)
D. m3/(kg2⋅s)
4. What happens to the gravitation force between two objects that are 15 m apart, when one of them moves 3 m closer?
A. It increases by a factor of 1 1/4
B. It decreases by a factor of 1 1/4
C. It increases by a factor of 1 9/16
D. It decreases by a factor of 1 9/16
5. In thinking about the uniform distribution of a gravitational field over a sphere, why does gravitational force have an inverse-square relationship with the distance between objects?
A. because the volume of a sphere is proportional to its radius
B. because the volume of a sphere is proportional to the square of its radius
C. because the surface area of a sphere is proportional to the square of its radius
D. because the surface area of a sphere is proportional to its radius
My answers:
1. B
2. C
3. A
4. B
5. D
7 answers
4 C
5 area = 4 pi r^2 and volume = (4 /3) pi r^3
like area = dV/dr = 3(4/3) pi r^2
1. B - The force decreases by a factor of 9.
2. C - 8
3. C - m3/(kg •s2)
4. B - It increases by a factor of 1 9/16.
5. D - because the surface area of a sphere is proportional to the square of it's radius.