Rotational Kinematics & Dynamics

A fan blade, initially at rest, rotates with a constant acceleration of 0.025 rad/s². What is the time interval required for it to reach a 4.2 rad displacement after starting from rest   

• 1.8 s

• 2.0 s

• 16 s

• 18 s

A 0.12-m-radius grinding wheel takes 5.5 s to speed up from 2.0 rad/s to 11.0 rad/s. What is the wheel's average angular acceleration?

• 9.6 rad/s²

• 4.8 rad/s²

• 3.1 rad/s²

• 1.6 rad/s²

A gear spins at a rate of 400 revolutions/minute. Which choice is closest to its angular speed in radians/second?

• 6.67 rad/s

• 2500 rad/s

• 41.9 rad/s

• 20.9 rad/s

A flywheel starts from rest, and has an angular acceleration of 4 rad/s². What will be its angular speed when it has made one revolution? 

• 5.01 rad/s

• 50.27 rad/s

• 2.83 rad/s

• 7.09 rad/s

Tags

NGSS.HS-PS3-2

What is 2 radians in degrees?

• 57.3

• 114.6

• 26.65

What is the angular displacement in radians if a paint spot on a tire turns from 57.3 degrees to 282 degrees?

• 12834 rad

• 224.7 rad

• 3.9 rad

• 180 rad

What is the average angular velocity in radians if a paint spot on a tire turns from 57.3 degrees to 282 degrees in 0.5 sec?

• 25668 rad/s

• 7.8 rad/s

• 449 rad/s

• 1.95 rad/s

The number of complete revolutions per second is:

• frequency

• period

• torque

• rotational inertia

A wrench is used to tighten a nut. A 15N perpendicular force is applied 50cm away from the axis of rotation, and moves a distance of 10 cm as it turns. What is the torque applied to the wrench?

• 7.5 Nm

• 1.5 Nm

• 750 Nm

• 150 Nm

The easiest way to open a heavy door  is by applying the force

• Near the hinges

• In the middle of the door

• At the edge of the door far from the hinges

• At the top of the door