(Multiple choice)

(1)

True/False

An object cannot move in a circle unless there is a net force acting on it?

(2)

An object moves in a circle counterclockwise with constant speed (Figure). Which figure shows the correct velocity and acceleration vectors?

(3)

A particle is traveling in a vertical circle at constant speed. One can conclude that the ________ is constant.

1. Velocity
2. Acceleration 
3. Net force
4. Apparent weight
5. None of the above.

(4)

A stone with a mass m = 95 g is being whirled in a horizontal circle on the end of a string that is 85 cm long. The length of time required for the stone to make one complete revolution is 1.22 s. The angle that the string makes with the horizontal is__________ 

(a) 52° 

(b) 46° 

(c) 26° 

(d) 23° 

(e) 3°

(5)

A person rides a loop- the-loop at an amusement park. The cart circles the track at a constant speed. At the top of the loop, the normal force exerted by the seat equals the person's weight, mg. At the bottom of the loop, the forces exerted by the seat will be_________. 

(a) 0 

(b) mg 

(c) 2mg 

(d) 3mg 

(e) Greater than mg, but the exact value cannot be calculated from the information given

(6)

The radius of curvature of a loop-the-loop roller coaster is 12.0 m. At the top of the loop, the force that the seat exerts on a passenger of mass m is 0.4mg. Find the speed of the roller coaster at the top of the loop.

(7)

Realizing that he has left the gas stove on, Aaron races for his car to drive home. He lives at the other end of a long, unbanked curve in the highway, and he knows that when he is traveling alone in his car at 40 km/h, he can just make it around the curve without skidding. He yells at his friends, "Get in the car! With greater mass, I can take the curve at a higher speed!" Carl says, "No, that will make you skid at an even lower speed." Bonita says, "The mass doesn't matter. Just get going!" Who is right?

Transcribed Image Text:

(a) (b) (C) (d)