Torque and Rotational Kinematics

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?

• 0.666 Nm
•  133.3 N
• 66.7 N
• 13.3 Nm

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 disk initially rotating counterclockwise (CCW) at a certain constant angular speed is suddenly being pulled on by two strings T₁ and T₂, where T₂ > T_1. What is going to happen next?

• The disk will continued rotating CCW at the constant angular speed.

• The disk will continued rotating CCW but it will speed up

• The disk will slow down and start rotating CW

• The disk will eventually stop rotating

Tags

NGSS.HS-PS2-1

How do you find the tangential speed of a rotating circle?

• v = ωr
• v = ωr²
• v = ωπ
• v = ωπr

If the translational velocity of an object is 3 m/s, and is located a distance of 2 m from the axis of rotation, what is the object's angular velocity?

• 0.67 rad/s
• 1.5 rad/s
• 5 rad/s
• 6 rad/s

How do you get the maximum torque?

• longer lever arm and more force at an acute angle
• shorter lever arm with more force perpendicularly
• shorter lever arm and more force perpendicularly
• longer lever arm with more force perpendicularly

Looking at the picture, which way will it rotate?

• Clockwise
• Counter clockwise
• Neither

Tags

NGSS.HS-PS2-1

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

Two masses of mass 10.0 and 6.0 kg are hung from massless strings at the end of a light rod. The rod is virtually weightless. A pivot (fulcrum) is placed off center and the system is free to rotate. If the 6.0 kg mass is 4.0 m away from the pivot, how far away is the 10.0 kg mass if the system is not rotating?

• 0.42 m

• 2.4 m

• 4.8 m

• 4.2 m

Two wheels are fixed to each other and are free to rotate about a frictionless axis through their concentric centers. Four forces are exerted tangentially to the wheels. As a result of the net torque on the wheels, the wheels will rotate-

• clockwise

• counterclockwise