AP Torque

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

A system consists of a disk rotating on a frictionless axle and a piece of clay moving toward it, as shown in the figure above. The outside edge of the disk is moving at a linear speed v, and the clay is moving at speed v/2. The clay sticks to the outside edge of the disk. How does the angular momentum of the system after the clay sticks compare to the angular momentum of the system before the clay sticks, and what is an explanation for the comparison?

• It is the same because there is no external torque acting on the system

• It is greater because the rotating mass increases, which increases the rotational inertia.

• It is less because the speed of the disk decreases when the clay sticks to it.

• It is less because the angular momentum if the clay opposes that of the disk.

A long rod is suspended by a frictionless bearing near its top. A lump of clay is projected from the right, collides with the block and sticks to it. Which one of the following statements is correct about the clay and rod system for this collision?

• The mechanical energy, linear momentum and angular momentum remain constant.

• The linear momentum and the angular momentum remain constant but the mechanical energy changes.

• Only the angular momentum remains constant.

• None of the quantities of mechanical energy, linear momentum, or angular momentum remain constant.

Tags

NGSS.HS-PS2-2

You apply force to a wrench to tighten a bolt. The wrench breaks in half. Select the best answer for what happens next. Assume the force applied remains constant.

• The torque is now half of what it was, because torque and distance are inversely proportional

• The torque is now half of what it was, because torque and distance are directly proportional

• The torque is now double of what it was, because torque and distance are inversely proportional

• The torque is now double of what it was, because torque and distance are directly proportional

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?

• 
• 
• 
• 

Looking at the picture, which way will it rotate?

• Clockwise

• Counter clockwise

• Neither

Torque can be positive or negative.

• True

• False

Torque causes angular acceleration.

• True

• False

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 force of 10 N is applied at a distance of 0.5 m from the pivot point. What is the torque produced?

• 5 Nm

• 10 Nm

• 15 Nm

• 20 Nm