Rotational Dynamics

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

Is torque independent of the location of the origin?

• Yes, always.
• Yes, as long as the origin is either in the center or on one end.
• No, you always need to specify the origin.

Torques cause changes in _______.

• velocity

• moment of inertia

• lever arm

• angular velocity

The lever arm is the ________ distance from the axis of rotation to the point where the force is exerted.

• angular

• displaced

• perpendicular

• none of these

Suppose a doorknob is placed at the center of a door. Compared with a door whose knob is located at the edge, what amount of force must be applied to this door to produce the torque needed to open it?

• 1/4 as much

• 1/2 as much

• Twice as much

• Four times as much

What is the point at which all of the mass of the body and be considered to be concentrated?

• Center of Mass

• Moment of Inertia

• Rotational Equilibrium

• Torque

An ice skater is spinning in a circle with his arms extended out. He then brings his arms in, what happens to his rotational velocity?

• It increases

• It decreases

• It stays the same

• He stops spinning immediately

Question 12: What is the net torque about the center of mass of the object? 

• a) 0
• b) Fd, clockwise
• c) Fd, counterclockwise
• d) 2Fd, clockwise or e) 2Fd, counterclockwise

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

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