work, rotational,

WORK

is done when the force that is exerted produces a displacement.

- direction of F and D are parallel

- θ = 0

- ex: pushing a book across the table

case 1 work

- F and d are opposite or antiparallel

- θ = 180

- ex: friction

case 3 work

- F is perpendicular to d

- θ = 90

- carrying a book while walking

case 2 work

POWER

- rate of doing work

- Watt/W or J/S

Mechanical Energy

Energy associated with a body's position and motion

Kinetic Energy

comes from the Greek word "kinetikos" , which means "motion.

work-energy theorem

- the network done on a system is equal to the change in its kinetic energy

POTENTIAL ENERGY

- associated with the position of objects

- measured with respect to or relative to a particular reference point

GRAVITATIONAL POTENTIAL ENERGY

the energy stored in an object by virtue of its height

from the center of the Earth

- Work done by gravity when the body is moving up

- F and D are antiparallel

- Ug2 > Ug1

- W = (-)

PE CASE 1

- Work done by gravity when the body is moving down

- F and D are parallel

- Ug2 < Ug1

- W = (+)

PE case 2

Conservative force

a force for which the work done DOES NOT depend on the path, but only on the initial and final positions

ELASTIC POTENTIAL ENERGY

the energy stored in a stretched or a compressed spring.

ROTATIONAL MOTION

- motion of a body that spins about an axis.

- undergo circular motion

Translational motion

- straight line motion (horizontal, free fall, projectile motion)

arc length

the cart moved a distance s, measured from the

circumference of the circle; s is?

Radian

an angle whose arc length is equal to the radius, which is

approximately equal to 57.3 degrees.

centripetal force

inward force

TORQUE

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

- Unit: N/M

- The effect that causes an object to rotate

- turning effect of a force

lever arm

The PERPENDICULAR distance from the axisof 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.

- measure of the object's resistance to a change in its rotational motion about some axis.

Angular Momentum

it refers to the quantity of motion that an object

has; mass in motion.