Active Learning: Rotational Kinematics Rev, 5/12

Active Learning: Rotational Kinematics rev, 5/12

I Rotational Kinematics

1. A rotor starts from rest and accelerates with constant angular acceleration to 30 rpm CW in 12 revolutions.

A. What is the final angular velocity in standard units?

B. What is the angular acceleration?

C. How many seconds did it take to come up to speed?

2. The angular velocity of a rotating disk varies with time according to

A. How many revolutions are completed in 10 seconds? B. What is the angular acceleration at 10 seconds?

II Angular versus Tangential Motion 1. Consider the two points A and B on a disc (R = 10 cm) that is rotating CCW (RA = 3 cm, RB = 8 cm) .

A. Which of the following statements are true (there may be more than one)? (Consider magnitudes only)

a. ωA > ωB c. ωA < ωB e. ωA = ωB

b. vA > vB d. vA < vB f. vA = vB Diameter = 22 cm

B. Draw velocity vectors for vA and vB. Diameter = 5 cm

Active Learning: Rotational Kinematics

2. The figure below represents a bicycle front and rear sprocket connected by a chain. The front sprocket is larger than the rear sprocket.

A. Which has the greater linear speed, the rim of the front sprocket, back sprocket or are they both equal?

B. Which has the greater rotational speed, the front sprocket, the back sprocket, or are they both the same?

3. A bicycle racer is traveling at 10 m/s with an acceleration of 0.5 m/s2. The radius of the bicycle wheel is 33 cm.

A. What is the tangential speed of a point on the rim of the bike wheel.

B. What is the angular velocity of the bicycle wheels?

C. What is the angular acceleration of the bicycle wheels?

D. What is the centripetal acceleration for a point on the rim of the wheels?