Torque and Angular momentum and energy

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

Tags

NGSS.HS-PS2-1

Does a bridge anchored resting on two pillars have any torque?

• No, it isn't moving
• Yes, but it is at equilibrium
• Yes, but it will soon break because of the torque
• No, Bridges can't have torque

The figure above shows a uniform meterstick that is set on a fulcrum at its center. A force of magnitude F toward the bottom of the page is exerted on the meterstick at the position shown. At which of the labeled positions must an upward force of magnitude 2F be exerted on the meterstick to keep the meterstick in equilibrium?

• A

• B

• C

• D

Tags

NGSS.HS-PS2-1

A flywheel's diameter is twice that of another of the same shape and mass. Roational inertia of the larger flywheel is

• two times greater

• four times greater

• the same as the other

• half that of the other

What happens to her angular velocity when a figure skater brings in her arms?

• Increases her angular velocity
• Decreases her angular velocity
• Has no affect

As shown in the figure, a given force is applied to a rod in several different ways. In which case is the torque about the pivot P due to this force the greatest?

• 1
• 2
• 3
• 4

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 uniform solid cylinder with a radius of 10 cm and a mass of 3.0 kg is rotating about its center with an angular speed of 33.4 rpm. What is its kinetic energy?

• 0.092 J
• 17 J
• 1.1 J
• 0.18 J

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-3

Find the angular momentum for a 5 kg solid cylinder with a 20 cm radius rotating at 3 rad/s.

• 3000 kg-m²/sec

• 0,3 kg-m²/sec

• 0,6 kg-m²/sec

• 1.2 kg-m²/sec

CONSERVATION OF ANGULAR MOMENTUM. A playground merry-go-round has a mass of 120 kg and a radius of 1.80 m. If it is rotating with an angular velocity of 3.14 rad/s, What is its angular velocity after a 22.0-kg child gets onto it by grabbing its outer edge? Consider it as a solid cylinder

• 3.14 rad/s

• 2.65 rad/s

• 2 rad/s

• 3.65 rad/s