1- Newton's law of gravitation is an inverse square law in which the field is a vector

where little g is the magnitude of the gravitational field, M is the mass responsible for the gravity, R is the distance to its center from the point of interest, and the little unit vector points toward the mass M from the point. Big G is Newton's constant of gravitation.

When you know the gravitational field, how do you find the force on a mass m located at that point?

a) The force is

b)The force is the mass being attracted times the field of the source of gravity, or

c)The force is a vector with a minus sign because it is attracting toward M

d)The force is the same as the vector field, that is

2- In a right triangle the two sides that are at 90 are 16and 14. What is the length of the hypothenuse?

3- Match the items about gravity. There are extra answers in your options, so take care in selecting the correct one. We will give partial credit if you miss some.

- A. B. C. D. E. F.	Newton's universal law of gravity
- A. B. C. D. E. F.	Approximate force of gravity on 1 kg near Earth's surface
- A. B. C. D. E. F.	Approximate force of gravity on the Earth from 1 kg near its surface
- A. B. C. D. E. F.	Change in potential energy of a mass m when it is moved a distance h in a direction away from Earth near its surface

A.	10 N upward
B.	mgh
C.	0
D.	GmM/R2
E.	10 N downward
F.

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