Rotational Motion AP

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

Tags

NGSS.HS-PS2-1

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/s/s
• 4.8 rad/s/s
• 3.1 rad/s/s
• 1.6 rad/s/s

Tags

NGSS.HS-PS2-1

Which has greater linear speed, a horse near the outside rail of a merry-go-round or a horse near the inside rail?

• the inside horse
• the outside horse
• Neither

A small mass on a string is rotating without friction in a circle. The string is shortened by pulling it through the axis of rotation with no external torque. What happens to the tangential velocity?

• It increases
• It decreases
• It stays the same

The relation between linear velocity and angular velocity

• r = v⍵

• ⍵ = vr

• v = r⍵

• a = v⍵

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

Tags

NGSS.HS-PS2-1

If the torque required to loosen a nut on the wheel of a car has a magnitude of 60.0 N• m, what minimum perpendicular force must be exerted by a mechanic at the end of a 45.0 cm wrench to loosen the nut?

• .666 Nm
•  133.3 N
• 66.7 N
• 13.3 Nm

The figure shows scale drawings of four objects, each of the same mass and uniform thickness, with the mass distributed uniformly. Which one has the greatest moment of inertia when rotated about an axis perpendicular to the plane of the drawing at point P?

• A
• B
• C
• D

A person sits on a freely spinning lab stool that has no friction in its axle. When this person extends her arms,

• her moment of inertia increases and her angular speed decreases.
• her moment of inertia decreases and her angular speed increases.
• her moment of inertia increases and her angular speed increases.
• her moment of inertia increases and her angular speed remains the same.

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