Physics: Chapter 8 Test Review

alpha equals net torque divided by the moment of inertia (fish=T/I)

Newton's 2nd law for rotational motion states angular acceleration is equal to _____________ (formula).

net torque

Newton's 2nd law of rotational motion states that angular acceleration is directly proportional to the ____________.

accelerated

Newton's laws do not apply to rotating frames of reference, because these frames are _____________ frames.

curved horizontal path

A person standing at the center of a rotating disk throws a ball towards the edge of the disk; the ball will appear to follow a _____________ by a person standing on the disk.

zero

A seesaw balances because the net torque is ______.

A factor of torque is the lever arm which uses the angle closest to the axis of rotation, not the perpendicular.

A wrench is being used at an angle 30 degrees from the perpendicular. Explain why the angle 60 degrees is used in the equation when calculating torque.

This raises the diver's center of mass up which creates the illusion of floating while it allows a greater force from the board and gives the diver more time.

Before a guy dives off the diving board, he raises his hands above his head. Explain what effect this action will have on his diving.

measure of how much an object resists rotation

Define moment of inertia.

an external force outside of the system could affect the state of rotation

Explain how a force of 30 N causes an object to rotate pi rad, but another force of 30 N using the same lever arm can cause the object to rotate (2/3) pi rad.

It depends on the distance from the axis of rotation and the location.

Explain why the formula for calculating the moment of inertia are different for objects of different shapes.

counterclockwise around low pressure areas

How does the Coriolis "force" make winds rotate in the north?

clockwise around low pressure areas

How does the Coriolis "force" make winds rotate in the south?

positive

If the angular velocity of an object is positive, its angular acceleration is ___________.

center of mass

The axis of rotation for a uniform, spinning disk is located at the ___________________ of the disc.

easterly/eastward

The horizontal motion of the projectile has a ________________ component if the projectile is thrown to the north from the equator.

stability

The lower center of mass of an object is located, the greater the __________ of that object.

They have the same angular velocity because they make the same revolutions per second. Her sister's linear velocity greater because she covers more distance per second.

Two sisters ride the carousel. One chooses a horse near the outer edge; the other chooses a horse closer to the center. Which sister experiences a greater linear velocity? Which sister has greater angular velocity?

amount of mass and location of mass

What 2 factors determine how much torque is needed to change angular velocity?

radians, gradiants, and degrees

What are the 3 units for an object's rotation?

both velocity and angular velocity are zero or constant, the net force equals zero (translational), and the net torque equals zero (rotational)

What are the three conditions for static equilibrium?

angular velocity (w=rad/sec)

What can you calculate if you know a disk completes a rotation every few seconds?

centripetal acceleration

What is apparently observed as centrifugal "force" is the effect of ________________________.

the perpendicular distance from the axis of rotation to the point where the force is exerted

What is the definition of a lever arm?

gravity is the only thing that affects vertical motion. The Coriolis "force" acts on the direction perpendicular to the rotation of axis and usually occurs on large scale things over large periods of time which are usually constrained to the surface of Earth (like the ocean). As you move horizontally, or closer to the equator, more force is required to keep you on the ground when you are going faster because of Earth's eastward rotation.

When observing the effects of the Coriolis "force," why is only the horizontal aspect of the motion considered? Why doesn't the Coriolis "force" affect vertical motion?

A sports car because there is a lower center of mass and so it takes a larger angle for it to tip over.

Which vehicle would be more stable on a sharp turn in the road: a minivan or a sports car? Explain your answer.

Rotational

___________ equilibrium means that the net torque on an object must be zero.

angular displacement

________________ is the change in the angle as an object rotates.