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Physics Pre-AP
Gravitation Multiple Choice
1.
The mass of the moon is 7.4X1022 kg and its mean radius is 1.75X103 km. What is the acceleration due to gravity at the
surface of the moon?
a. 2.8X106 m/s2
b. 9.80 m/s2
c. 1.6 m/s2
d. 0.80 m/s2
2.
The gravitational attractive force between two masses is F. If the masses are moved to half of their initial distance, what is
the gravitational attractive force?
a. F/4
b. F/2
c. 2F
d. 4F
3.
The gravitational attractive force between two masses is F. If the masses are moved to twice of their initial distance, what is
the gravitational attractive force?
a. F/4
b. F/2
c. 2F
d. 4F
4.
A hypothetical planet has a mass of half that of the earth and a radius of twice that of the earth. What is the acceleration due
to gravity on the planet in terms of g, the acceleration due to gravity at the earth?
a. g
b. g/2
c. g/4
d. g/8
5.
An object weighs 432 N on the surface of the earth. The earth has radius r. If the object is raised to a height of 3r above the
earth's surface, what is its weight?
a. 432 N
b. 48 N
c. 27 N
d. 0 N
6.
A spaceship is traveling to the moon. At what point is it beyond the pull of earth's gravity?
a. When it gets above the atmosphere.
b. When it is half-way there.
c. When it is closer to the moon than it is to earth.
d. It is never beyond the pull of earth's gravity.
7.
Satellite A has twice the mass of satellite B, and rotates in the same orbit.
a. The speed of B is twice the speed of A.
b. The speed of B is half the speed of A.
c. The speed of B is one-fourth the speed of A.
d. The speed of B is equal to the speed of A.
8.
The acceleration of gravity on the moon is one-sixth what it is on earth. An object of mass 72 kg is taken to the moon. What
is its mass there?
a. 12 kg
b. 72 kg
c. 72 N
d. 12 N
9.
Consider a small satellite moving in a circular orbit (radius r) about a spherical planet (mass M). Which expression gives this
satellite's orbital velocity?
a. v = GM/r
b. (GM/r)1/2
c. GM/r2
d. (GM/r2)1/2
10.
Compared to its mass on the earth, the mass of an object on the moon is
a. less.
b. more.
c. the same.
d. half as much.
11.
The speed of Halley's comet, while traveling in its elliptical orbit around the sun,
a. is constant.
b. increases as it nears the sun.
c. decreases as it nears the sun.
d. is zero at two points in the orbit.
12. Know Kepler’s Laws (3)
Physics Pre-AP
Circular Motion Multiple Choice Practice
13.
A car goes around a curve of radius r at a constant speed v. What is the direction of the net force on the car?
a. toward the curve's center
b. away from the curve's center
c. toward the front of the car
d. toward the back of the car
14.
A roller coaster car (mass = M) is on a track that forms a circular loop (radius = r) in the vertical plane. If the car is to just
maintain contact with the track at the top of the loop, what is the minimum value for its speed at that point?
a. gr
b.
gr
c.
2rg
d.
1
rg
2
15.
A car goes around a curve of radius r at a constant speed v. Then it goes around a curve of radius 2r at speed 2v. What is the
centripetal acceleration on the car as it goes around the second curve, compared to the first?
a. one fourth as big
b. one half as big
c. twice as big
d. four times as big
16.
If a car goes around a curve at half the speed, the centripetal force on the car is
a. twice as big.
c.
half as big.
b. Four times as big.
d.
one-fourth as big.
17.
A car goes around a curve of increasing radius. What happens to the centripetal force on the car?
a. It decreases.
b. It increases.
c. It remains constant.
d. It is impossible to predict because it depends on other factors not given here.
18.
A stone, of mass m, is attached to a strong string and whirled in a vertical circle of radius r. At the exact top of the path the
tension in the string is 3 times the stone's weight. The stone's speed at this point is given by
a.
2 rg
b.
2rg
c.
rg
d. 2gr
19.
A pilot executes a vertical dive, then follows a semi-circular arc until it is going straight up. Just as the plane is at its lowest
point, the force on him is
a. less than mg, and pointing up.
b. less than mg, and pointing down.
c. more than mg, and pointing up.
d. more than mg, and pointing down.
20.
A car goes around a curve of radius r at a constant speed v. Then it goes around a curve of radius 2r at speed v. What is the
centripetal force on the car as it goes around the second curve, compared to the first?
a. one-fourth as big
b. one-half as big
c. twice as big
d. four times as big
21.
Consider a particle moving with constant speed such that its acceleration of constant magnitude is always perpendicular to its
velocity.
a. It is moving in a straight line.
b. It is moving in a circle.
c. It is moving in a parabola.
d. None of the above is definitely true all of the time.
22.
A coin of mass m rests on a turntable a distance r from the axis of rotation. The turntable rotates with a frequency of f. What
is the minimum coefficient of static friction between the turntable and the coin if the coin is not to slip?
a. (42f2r)/g
b. (42fr2)/g
c. (4f2r)/g
d. (4fr2)/g
23.
An object moves in a circular path at a constant speed. Consider the direction of the object's velocity and acceleration
vectors.
a. Both vectors point in the same direction.
b. The vectors point in opposite directions.
c. The vectors are perpendicular.
d. The question is meaningless, since the acceleration is zero.