Definitions
What is the time it takes for one complete revolution called?
Period (T)
What is the relationship between period (T) and Frequency (f)
Inversely related
If an object is moving in a circle at constant speed, is it accelerating?
Yes, because its direction is changing
A motion has a period of 2 seconds. What is its frequency?
f= 1/T
0.5 Hz
If centripetal force suddenly becomes zero, what happens to the motion?
The object moves in a straight line
What is the number of cycles completed per second called?
Frequency (f)
If you double the speed of an object in circular motion, what happens to the centripetal force?
It quadruples
What provides the inward force when you swing an object on a string?
Tension
An object makes 10 revolutions in 20 seconds. What is the frequency?
f= n/t
0.5 Hz
A 2 kg object moves in a circle at 4 m/s with a radius of 2 m. What is the centripetal acceleration?
a= v^2/r
8 m/s2
What is the force that keeps an object moving in a circle called?
Centripetal Force
If you double the radius (same speed), what happens to centripetal force?
It decreases (cut in half)
Why don’t we use velocity (vector) the same way in circular motion?
Because direction is constantly changing
Why do we time multiple revolutions instead of just one in experiments?
To reduce error and improve accuracy
A 3 kg object moves at 6 m/s in a circle of radius 3 m. What is the centripetal force? (First find acceleration, then force)
a= v^2/r
F=ma
36N
What is the direction of centripetal acceleration?
Toward the center of the circle
If you double the mass, what happens to centripetal force?
It doubles
What provides centripetal force for a car turning on a road?
Friction
An object makes 12 revolutions in 24 seconds. What is the period?
T= t/n
2 seconds per revolution
An object moves in a circle of radius 2 m and completes one revolution in 4 seconds. The mass is 2 kg. What is the centripetal force?
A. 4.9 N
B. 9.9 N
C. 19.7 N
D. 39.5 N
V=(2pir) /T
a=v^2/r
F=ma
B. 9.9 N
What is the velocity of an object moving along a circular path called?
Tangential Velocity
If radius decreases while speed stays the same, what happens to centripetal acceleration?
It increases.
Why does a tighter turn feel “stronger” in a car? (Think about what is happening to the radius)
Smaller radius → greater centripetal acceleration/force
A spinning object has a frequency of 5 Hz. What is its period?
T= 1/f
0.2 seconds
A 1.5 kg object moves in a circle of radius 1.5 m at a speed of 3 m/s. If the speed is doubled, what is the new centripetal forcce?
A. 9 N
B. 18 N
C. 27 N
D. 36 N
F= (mv^2) / r
D. 36 N