Period, Frequency, Speed
Fc = ?
Horizontal Circle Problems
Vertical Circle Problems
Grab Bag
100
A turntable completes one full rotation every 1.2 seconds. What is the turntable's frequency in Hz (round to the nearest hundredth)?
0.83 Hz
100
A ball attached to a string is whirled in a horizontal circle.
Fc = FT
100
A 0.2 kg ball is twirled in a horizontal circle with a radius of .6 meters. If the speed of the ball is 2 m/s, what is the tension in the string?
1.3 N
100
A 0.2 kg ball is twirled on a 0.5. meter long string in a vertical circle at a speed of 1.5 m/s. What is the tension force in the string when the ball is at the bottom of the loop?
2.9 N
100
Can an object accelerate when traveling at a constant speed? How?
Yes. If an object is turning, its velocity is changing, so it is accelerating.
200
A ceiling fan rotates at 2.5 Hz. How many full rotations does it make in 1 minute?
150 rotations
200
A car is driving on a flat roundabout.
Fc = Ff (static)
200
A 0.3 kg ball is twirled in a circle with radius 0.7 meters. If the tension in the string is 2.5 N, how fast is the ball traveling?
2.4 m/s
200
A 0.2 kg ball is twirled on a 0.5 meter long string in a vertical circle at a speed of 1.5 m/s. Is this fast enough for the ball to make it over the top of the loop? Why or why not?
No, it is not fast enough. The weight (Fg) is larger than the centripetal force.
200
A child fills a bucket of water and swings it in an arc over his head, as shown below. Why doesn't the water spill on his head when it is at the top of the circle?
The water's inertia prevents it from falling onto the boy's head.
300
A toy car moves in a circle with radius of 0.8 meters. It makes one circle every 3 seconds. Calculate the speed in m/s (round to the nearest hundredth).
1.68 m/s
300
A ball is whirled on a string in a vertical circle. The ball is located at the bottom of the circle.
Fc = FT - Fg
300
A bicycle of mass 3 kg is turning in an arc of radius 10 meters at a speed of 4 m/s. How much friction force is acting on the car to allow it to turn without slipping?
4.8 N
300
A 1,200 kg car is driving over a hill with radius 25 meters at a speed of 10 m/s. What is the apparent weight of the car?
FN = 7,200 N
300
Short track speed skaters practice on a circular track of radius 18 meters. If the top speed of the skater is 22 m/s, how long does it take the skater to make one loop of the track (round to the nearest hundredth)?
5.14 seconds
400
A cyclist rides around a circular track with a radius of 120 meters at a speed of 15 m/s. What is his period of motion (round to the nearest seconds)?
50 seconds
400
A ball is whirled on a string in a vertical circle. The ball is located at the top of the circle.
Fc = FT + Fg
400
A bicycle of mass 4 kg is turning in an arc of radius 10 meters. If the coefficient of friction between the tires and the road is 0.65, how fast can the bicycle travel before the wheels begin to slip?
8 m/s
400
A 1,250 kg car drives into a dip of radius 15 m at a speed of 22 m/s. What is the apparent weight of the car?
FN = 52,833 N
400
When a roller coaster car is located at the top of an upside down roller coaster loop, what direction does the normal force point? Why? 
Downward. The normal force is generated by the track pushing on the roller coaster car.
500
Two objects move in uniform circular motion.
Object A moves in a circle of radius 0.40 m with a frequency of 3.0 Hz.
Object B moves in a circle of radius 0.75 m and has a period of 0.80 s.
Which object is moving faster and why?
Object A
Object A is moving at a speed of about 7.5 m/s while Object B is moving at a speed of about 5.9 m/s
500
A car is driving over the top of a hill.
Fc = Fg - FN
500
A 50 kg person riding the rotor ride at a carnival travels at 7.5 m/s. The person slides up the wall so that their feet are no long in contact with the ground. If the person is located 2.5 meters from the center of the ride, how much normal force does the person experience? 
1,125 N
500
A 1,500 kg car driving into a dip of radius 12 m experiences a normal force of 30,000 N. How fast is the car driving?
11 m/s
500
A 300 kg roller coaster car is located at the top of an upside down loop of radius 10 meters. If the car is traveling at a speed of 12 m/s, what is the apparent weight of the roller coaster car? 
1,320 N