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

Find the magnitude of the torque produced by a 5.0 N force applied to a door at a perpendicular distance of 65 cm from the hinge.

• 75 Nm
• 3.25 Nm
• 6.3 Nm
• 8.75 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

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?

• 
• 
• 
• 

Which has greater angular 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 - they both have the same angular speed

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