Rotational Dynamics and Equilibrium

What does the symbol Δω mean?

• angular acceleration

• angular velocity

• change in angular acceleration

• change in angular velocity

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

• Yes, but it will soon break because of the torque

• No, it isn't moving

• No, Bridges can't have torque

• Yes, but it is at equilibrium

Tags

NGSS.HS-PS2-3

A person stands a distance  $\overrightarrow{r}$   from a door’s hinges and pushes with a force  $\overrightarrow{F}$   directed perpendicular to its surface, rotating the door at its hinge with a torque  $\tau$  . What is the applied torque if the person’s position and force change to  $\overrightarrow{2r}$   and  $\overrightarrow{2F}$  , respectively?

•  $\tau$  

•  $2\tau$  

•  $4\tau$  

•  $\frac{\tau}{4}$  

Signs are suspended from rods of equal length on the side of a building. For each case, the mass of the rod can be ignored. The mass of the sign is given in each figure. Which case has the greatest magnitude of the torque that the sign exerts about the point at which the rod is attached to the side of the building.

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A 2-m long massless rod supports a 12-Newton weight. The left end of each rod is held in place by a frictionless pin. In each case, a vertical force F is holding the rods and the weights at rest. The rods are marked at half-meter

intervals. Which case has a force F with the greatest magnitude?

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Tags

NGSS.HS-PS2-1

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

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

A 800N man is playing on a seesaw with son who has a weight of 200N. If the child is sitting 3 meters away, how far will the man have to sit to balance the seesaw?

• 0.75m
• 3m
• 1.5m
• 1m

Tags

NGSS.MS-PS2-4