Physics 121 General Physics
Concept Quizzes
Chapter 6. Circular Motion and Other Applications of Newton's Laws

A boy and a girl are riding on a merry-go-round which is turning at a constant rate. The boy is near the outer rim and the girl is closer to the centre of rotation.

1. How do the magnitudes of their accelerations compare?

	The girl's is greater.
	The boy's is greater.
	The boy and the girl both have zero acceleration.
	They both have the same non-zero magnitude acceleration.

2. Who has to hold on tighter? (Assume they both have approximately the same mass.)

	The boy.
	The girl.
	Both the same.

A piece of mud flies off the rim of a bycicle wheel. In what direction will it be going immediately after leaving the wheel? (Ignore gravity in this short time interval.)

	On a line directly away from the center of the wheel.
	On a line at a tangent to the edge of the wheel.
	On a curved path moving around the wheel.
	On a stright line directed somewhere between answers A and B above.

What force is responsible for holding a car in an unbanked curve?

	The car's weight.
	The vertical component of the normal force.
	The horizontal component of the normal force.
	The force of friction.

What force is responsible for holding a car in a frictionless banked curve?

	The car's weight.
	The vertical component of the normal force.
	The horizontal component of the normal force.
	The force of friction.

What force is responsible for holding a car in a banked curve with friction?

	The car's weight.
	Just the vertical component of the normal force.
	Just the horizontal component of the normal force.
	Just the force of friction.
	A combination of the force of friction and the horizontal component of the normal force.

A rider in a "Barrel of Fun" finds herself stuck to the wall when the floor has dropped away. Which is a correct Free Body Diagram of the forces acting on her?