Practice Questions (Chapter 5)

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

(A) the tension is towards the center of the circle and the net force is down.
(B) the weight is down and the net force is towards the center of the circle.
(C) the tension force is towards the center of the circle and the weight is down.
(D) the weight and tension are in the same direction.

2. 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?

(A) g downward
(B) g upward
(C) 0.5 g downward
(D) 2 g upward

3. 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

(A) of A and B are the same.
(B) of A is twice that B.
(C) of A is four times that of B.
(D) of A is half that of B.

4. 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

(A) part of a parabola.
(B) part of a circle.
(C) a hyperbola.
(D) part of an ellipse.

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

(A) Gravity
(B) Electric
(C) Nuclear
(D) Weak

6. 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

(A) opposite the friction force.
(B) in the direction of the friction force.
(C) perpendicular to the surface.
(D) is along the rod.


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

(A) twice the old force.
(B) half the old force.
(C) four times the old force.
(D) one fourth the old force.
(E) The same as the old force.

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

(A) twice the old force.
(B) half the old force.
(C) four times the old force.
(D) one fourth the old force.
(E) the same as the old force.


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

(A) twice the old force.
(B) half the old force.
(C) four times the old force.
(D) one fourth the old force.
(E) the same as the old force.


10. 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

(A) twice the old force.
(B) half the old force.
(C) four times the old force.
(D) one fourth the old force.
(E) the same as the old force.


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

(A) Newton's Law of Gravity.
(B) Kepler's First Law.
(C) Kepler's Second Law.
(D) Kepler's Third Law.


12. Which of the following does not belong with the others?

(A) A car speeds up from 30 mph to 40 mph.
(B) A car breaks from 20 mph to 0.
(C) A race car rounds a curve at 120 mph.
(D) A car coasts down a road at constant speed.


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

(A) Moon and the Earth.
(B) Moon and the Space Shuttle.
(C) Earth and the Sun.
(D) Moon and the Sun.

14. If the mass of the Earth was quadrupled and nothing else was changed

(A) g would increase by a factor of 4.
(B) g would increase by a factor of 2.
(C) g would decrease by a factor of 1/2.
(D) g would decrease by a factor of 1/4.

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

(A) four times that of Earth.
(B) two times that of Earth.
(C) 1/2 that of Earth.
(D) 1/4 that of Earth.



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

(A) depends on the value of the mass.
(B) is at 45 degrees.
(C) is at 225 degrees.
(D) zero.

17. The speed of a satellite in orbit does not depend on

(A) its mass.
(B) the mass of the Earth.
(C) its distance above the Earth's surface.