Rotational Kinematics
Connecting Linear and Rotational Motion
Torque
Rotational Inertia
Newton's Laws
100
A wheel spins at 2 rad/s for 5 s. What is its angular displacement?
10 rad
100
A solid disk rotates about point O. Three points are shown: P, R, Q.
Which point has a greater angular displacement after the wheel rotates for t = 2s? 
They all have the same angular displacement
100
Two wheels are fixed to each other and are free to rotate about a frictionless axis through their concentric centers. Four forces are exerted tangentially to the wheels. The magnitude of the net torque is...
4FR
100
What two main factors affect rotational inertia?
Mass & distribution of mass
100
Condition for rotational equilibrium?
∑τ=0
200
Compare the average angular speeds of the fans.
w3>w2>w1
200
Two people are sitting on a large metal disk at a park. The disk accelerates from rest until it reaches a certain angular velocity. How do their angular accelerations ad tangential acceleration compare? 
Same angular acceleration, Person 2 has a larger tangential acceleration.
200
10 N force, 0.5 m lever arm, perpendicular. Find torque.
5 Nm
200
Hoop vs. solid disk (same mass & radius): which has greater I?
Hoop
200
30 kg child 2 m from pivot. Where should 20 kg child sit for balance?
3 m
300
The graph shows the angular velocity of a rotating wheel as a function of time. Describe the motion of the wheel.
The wheel is speeding up and rotating in a counter-clockwise direction. It has a positive acceleration.
300
Wheels A and B are connected by a moving belt and free to rotate about their centers, as shown. The belt does not slip on the wheels. Radius of Wheel B is twice the radius of Wheel A. How would their angular velocities and linear velocities compare?
Same linear velocity. Wheel B would have a smaller angular velocity.
300
Two masses are hung from massless string at the ends of a light rod. The pivot is off center and the system is free to rotate. How far is the 10 kg mass from the pivot if the system is NOT rotating?
2.4 m
300
A rod is made of three segments of equal lengths with different masses. Total mass of the rod is 6m. 
Where would the axis of rotation be located in order to minimize the rotational inertia of the rod?
About the right end
300
In equilibrium: what about net force & net torque?
Both = 0
400
The graph shows the angular velocity of a rotating wheel as a function of time. What is the angular displacement of the wheel in 10 seconds?
25 radians
400
A disc has a radius of 5 cm. If the disc rotates about its central axis at an angular speed of 8 revolutions per second, what is the linear speed of a point on the rim of the disc?
2.51 m/s
400
General torque formula?
τ=rFsinθ
400
Three flat objects have the same mass M and out dimension. The small circle at the center of each figure represents the axis of rotation. Which has the greatest moment of inertia? 
Square Loop
400
Uniform beam, two supports: what must forces satisfy?
∑F=0,∑τ=0
500
A graph of the angular velocity as a function of time is shown for an object that rotates about an axis. Compare the angular displacement during each time interval?
2 > 3 = 1
500
A wheel of radius R is initially at rest when it begins spinning about a central axis with constant angular acceleration. A point on the rim moves a distance of s over a time interval t. Write an expression for the angular acceleration of the wheel.
2s/Rt2
500
Torque τ(t)=4t Nm. Angular displacement after 2 s?
~8 rad
500
What is the moment of inertia at a point L/4 away from the center?
(7/48)ML2
500
3 m plank, mass 20 kg, supports 2 m apart. Max distance for 70 kg person before tipping?
~0.71 m