Physics 011

A of PQ#5

Chapter 5: Circular Motion; Gravitation
Practice Questions

 1

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

2gr

4gr

 2

A stone, of mass m, is attached to a strong string and whirled in a vertical circle of radius r. At the exact bottom 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

2gr

4gr

 3

A stone is whirled in a vertical circle on a cord. Halfway up

the tension is towards the center of the circle and the net force is down.

the weight is down and the net force is towards the center of the circle.

the tension force is towards the center of the circle and the weight is down.

the weight and tension are in the same direction.

 4

A roller coaster car is on a track that forms a circular loop 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 centripetal acceleration at this point?

g downward

g upward

0.5 g downward

2 g upward

 5

A girl attaches a rock to a string, which she then swings counter- clockwise in a horizontal circle. The string breaks at point P on the sketch, which shows a bird's-eye view (i.e., as seen from above). What path will the rock follow?

A

B

C

D

E

 6

The following statements refer to man-made, artificial satellites in orbit around earth. Which is an accurate statement?

It is possible to have a satellite traveling at either a high speed or at a low speed in a given circular orbit.

Only circular orbits (and not elliptical ones) are possible for artificial satellites.

A satellite in a large diameter circular orbit will always have a longer period of revolution about the earth than will a satellite in a smaller circular orbit.

The velocity required to keep a satellite in a given orbit depends on the mass of the satellite.

 7

Two objects are travelling in circular orbits. Object A is travelling at twice the velocity of object B in a circle with a diameter of twice that of B. The centripetal acceleration

of A and B are the same.

of A is twice that B.

of A is four times that of B.

of A is half that of B.

 8

A cannon ball is fired horizontally off a high cliff over a great distance. If air resistance can be ignored the path it follows is

part of a parabola.

part of a circle.

a hyperbola.

part of an ellipse.

 9

The variation of g over the surface of the earth does not depend upon

the shape of the Earth.

changes in elevation.

rotation of the Earth.

the subsurface structure of the Earth.

 10

There are four forces in nature. Which one allows you to close a door by pushing on it?

Gravity

Electric

Nuclear

Weak

 11

A ball of mass m is moving in a circle with uniform speed on a horizontal surface with friction at the end of a radial metal rod. The net force is

opposite the friction force.

in the direction of the friction force.

perpendicular to the surface.

is along the rod.

 12

Two bodies of equal mass are separated by a distance R. If you double the distance between them the new gravitational force will be

twice the old force.

half the old force.

four times the old force.

one fourth the old force.

The same as the old force.

 13

Two bodies of equal mass are separated by a distance R. If you double each mass then the new force will be

twice the old force.

half the old force.

four times the old force.

one fourth the old force.

the same as the old force.

 14

Two bodies of equal mass are separated by a distance R. If you double one mass then the new force will be

twice the old force.

half the old force.

four times the old force.

one fourth the old force.

the same as the old force.

 15

Two bodies of equal mass are separated by a distance R. If you double each mass and double the distance between them, the new force will be

twice the old force.

half the old force.

four times the old force.

one fourth the old force.

the same as the old force.

 16

The Earth moves faster in the winter when its closest to the Sun. This is an example of

Newton's Law of Gravity.

Kepler's First Law.

Kepler's Second Law.

Kepler's Third Law.

 17

Which of the following does not belong with the others?

A car speeds up from 30 mph to 40 mph.

A car breaks from 20 mph to 0.

A race car rounds a curve at 120 mph.

A car coasts down a road at constant speed.

 18

Kepler's Third Law can be used to relate the motions of the

Moon and the Earth.

Moon and the Space Shuttle.

Earth and the Sun.

Moon and the Sun.

 19

If the mass of the earth was quadrupled and nothing else was changed

g would increase by a factor of 4.

g would increase by a factor of 2.

g would decrease by a factor of 1/2.

g would decrease by a factor of 1/4.

 20

A planet with twice the mass and twice its radius has a value of g

four times that of Earth.

two times that of Earth.

1/2 that of Earth.

1/4 that of Earth.

 21

Four equal masses are arranged in a perfect square. The direction of the force on the one in the lower left hand corner

depends on the value of the mass.

is at 45 degrees.

is at 225 degrees.

zero.

 22

Four equal masses are arranged in a perfect square. The magnitude of the force on the one in the lower left hand corner due to the one diagonally across from it

would be equal to the magnitude force from either of the other two bodies.

would be equal to the magnitude of the sum of the forces of the other two bodies.

would be half the magnitude of the force from either of the other two masses.

would equal twice the magnitude of the force from either of the other masses.

 23

The speed of a satellite in orbit does not depend on

its mass.

the mass of the Earth.

its distance above the Earth's surface.

 24

The period of planet X is .62 Earth years and that of planet Y is 1.9 years.

Planet Y is closer to the Sun than planet X.

Planet Y is closer to the Sun than Earth.

The Earth is closer to the Sun than planet X.

The Earth is between planet X and planet Y.

 25

Which of the following does not belong with the others?

A person jumping off a diving board.

A high jumper.

A person standing on a scale.

An astronaut in an earth orbit doing a free space walk.