AP Physics Chapter 8

Torque characteristics

1. Distance : farther away = less force 2. Direction: clockwise (-) counterclockwise (+) 3. Has to be perpendicular

Torque

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

What does it mean for an object to be elastic?

It is able to bend and stretch and move back to its original shape

What does it mean for an object to be at static equilibrium?

It is not moving or rotating. It is motionless.

What is "Young's Modulus"? Is it the same for all objects?

It's the amount of stiffness a material has. It is also different for all materials.

What does elastic limit mean?

It's the point that once exceeded a spring is deformed or will not go back to its original shape.

What does the "k" stand for in Hooke's Law equation? Is k the same for all springs?

K stands for spring constant. The spring constant is unique for each spring.

If a spring experiences a rightward displacement, what direction will the spring force be pointed?

Leftward, it is always in the opposite direction

Moment of inertia

Measure of object's resistance to change in rotational motion

Translational equilibrium

No net forces acting on object

Rotational equilibrium

No net torque acting on object

Are there any objects that don't have any elasticity to them?

No, if you look at the atomic level all objects have some elasticity or some give to them.

Torque force is applied...

On a lever arm at some distance away from axis of rotation

What are some examples of objects that show a great amount of elasticity?

Rubber Bands and springs

Force to cause torque

The force must be applied perpendicular to the lever arm

Lever arm

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

What is the net force and net torque at static equilibrium?

They are both equal to zero

Why do you lean forward when you get out of your chair?

To move your center of gravity over your feet aka base of support

When is a spring at equilibrium?

When it is at rest aka not being stretched or compressed.

When does an object become unstable?

When its center of gravity is outside of its base of support.

Equilibrium

at rest

negative torque

clockwise

Positive torque

counterclockwise

How can you increase the stability of an automobile to prevent it from experiencing a rollover?

increasing the base of support or lowering the center of gravity.