Physics: Chapter 8 Rotational Equilibrium and Dynamics

angular momentum

The product of a rotating object's moment of inertia and the angular speed about the same axis.

center of mass

The point at which all the mass of the body can be considered to be concentrated when analyzing translational motion.

lever arm

The perpendicular distance from the axis of rotation to a line drawn along the direction of the force.

moment of inertia

The tendency of a body rotating about a fixed axis to resist a change in rotational motion.

rotational kinetic energy

The energy of an object due to its roational energy.

torque

A quantity that measures the ability of a force to rotate an object around some axis.

axis of rotation

The imaginary point or line around which an object rotates

extended object

An object that has a definite, finite size and shape.

symbol for torque

The Greek letter tau is the __________.

perpendicular

At an angle of 90? to a given line, plane, or surface.

center of gravity

equivalent to the center of mass

Newton's second law of motion

The acceleration of an object depends on the mass of the object and the amount of force applied.

translational motion

Motion in a straight line. Definite direction.

point mass

In physics, this is an object with a nonzero mass and no other properties or structure.

inclined plane

Identify the simple machine shown in the figure.

wedge

Identify the simple machine shown in the figure.

screw

Identify the simple machine shown in the figure.

lever

Identify the simple machine shown in the figure.

wheel and axle (or pulley)

Identify the simple machine shown in the figure.

simple machine

changes the direction or magnitude of an input force

input force

the force you exert on a machine

output force

the force exerted by a machine

The distance moved increases.

* When a machine decreases the force acting on an object, what happens to the distance the object moved?

The distance moved decreases.

* When a machine increases the force acting on an object, what happens to the distance the object moved?

A machine can increase or decrease the force acting on an object at the expense or gain of the distance moved.

* Explain how the operation of a simple machine alters the applied force and the distance moved.

Net torque is equal to an object's momentum of inertia multiplied by its angular acceleration.

* Describe Newton's second law of rotation.

the more torque is produced

The farther the force is from the axis of rotation, _____________.

both the ball's linear and rotational speeds

The total kinetic energy of a baseball thrown with a spinning motion is a function of ________.

farthest from the axis of rotation

Where should a force be applied on a lever arm to produce the most torque?

middle of inside curve

Where is the center of mass for a boomerang?