chapter 4 RAT

Question 1

The Moon falls toward Earth in the sense that it falls
A. with an acceleration of 10 m/s2, as do apples on Earth.
B. beneath the straight-line path it would follow without gravity.
C. both of these
D. neither of these

Answer 1

B. beneath the straight-line path it would follow without gravity

Question 2

The force of gravity between two planets depends on
A. their masses.
B. the square of the distance between their centers.
C. the constant G.
D. all of these

Answer 2

D. all of these

Question 3

Inhabitants of the International Space Station are weightless because
A. very little (if any) gravitational attraction to Earth is present.
B. in outer space one has no mass.
C. they lack a support force.
D. all of these

Answer 3

C. they lack support force

Question 4

A spacecraft on its way from Earth to the Moon is pulled equally by Earth and the Moon when it is
A. closer to the Earth’s surface.
B. closer to the Moon’s surface.
C. halfway from Earth to Moon.
D. at no point, since Earth always pulls more strongly.

Answer 4

B. closer to the Moon’s surface

Question 5

Theoretically, a baseball tossed horizontally in a gravity-free region would continue in a straight line. With gravity, it falls in one second about
A. 1 m below that line.
B. 5 m below that line.
C. 10 m below that line.
D. none of these

Answer 5

B. 5 m below that line

Question 6

When no air resistance acts on a projectile, its horizontal acceleration is
A. g.
B. at right angles to g.
C. centripetal.
D. zero.

Answer 6

D. zero

Question 7

Without air resistance, a ball tossed at an angle of 40° with the horizontal goes as far downrange as one tossed at the same speed at an angle of
A. 45°.
B. 50°.
C. 60°.
D. none of these

Answer 7

B. 50°

Question 8

When you toss a projectile sideways, it curves as it falls. It will become an Earth satellite if the curve it makes
A. matches the curve of Earth’s surface.
B. results in a straight line.
C. spirals out indefinitely.
D. none of these

Answer 8

A. matches the curve of Earth’s surface

Question 9

A satellite in elliptical orbit about Earth travels fastest when it moves
A. closest to Earth.
B. farthest from Earth.
C. neither of these; that is, it moves at the same speed everywhere.
D. halfway between the near and far points from Earth.

Answer 9

A. closest to Earth

Question 10

A satellite in Earth orbit is mainly above Earth’s
A. atmosphere.
B. gravitational field.
C. both of these
D. neither of these

Answer 10

A. atmosphere