Rotational Motion Review

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

A solid sphere, solid cylinder, and a hollow pipe all have equal masses and radii. If the three of them are released simultaneously at the top of an inclined plane and do not slip, which one will reach the bottom first?

• cylinder
• pipe
• sphere
• They all reach the bottom at the same time.

Tags

NGSS.HS-PS2-1

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.

Suppose you are designing an engineless car for a downhill coasting race. What type of wheels would be the best?

• Solid disks.

• Hoops.

• Hollow cylinders.

• Diamond encrusted triangles.

Tags

NGSS.MS-ETS1-1

NGSS.MS-ETS1-2

NGSS.MS-PS2-2

Which would have a greater linear velocity?

• Kid near the center of the merry go round
• Kid near the outside of the merry go round
• neither

A solid metal bar is at rest on a horizontal frictionless surface. It is free to rotate about a vertical axis at the left end. The figure shows forces of different magnitudes that are exerted on the bar at different locations. In which case does the bar's angular speed about the axis increase at the fastest rate?

• 
• 
• 
• 

Jenny stands on the edge of a diving board. The diving board length is 3.0 meters from where it is fixed to the scaffold. Jenny's mass is 60 kg. Calculate the torque Jenny puts on the edge of the diving board.

• 180 N∙m

• 20 N∙m

• 1766 N∙m

• 589 N∙m

What is the weight of the package?

• 5 N
• 10 N
• 15 N
• 20 N

Tags

NGSS.HS-PS2-1

What force is equal to the normal force from the wall acting on the ladder?

• Friction from the floor
• Normal force from the floor
• Friction from the wall
• Weight of the ladder

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