Work and Energy

Work/Power

100

Equation for Work

F x d

200

Equation for Power

W/t

300

Unit for Power

Watt

400

Work done equals change in _________

Energy

500

How much work is done by pushing a 40N crate a distance of 10m?  (Must use correct unit.)

400 Joules

Simple Machines

100

A ramp and stairs are examples of this type of machine.

Inclined Plane

200

Equation for mechanical advantage.

F-out/F-in

300

Ideal mechanical advantage uses ________ instead of force.

distance/displacement

400

What is the efficiency of a machine that uses 20 joules of work to produce 17 joules of work?

85%

500

T or F

A machine can multiply work.

False

Conservation of Energy

100

Can energy be created or destroyed?

No

200

Equation for conservation of energy.

MA=KE+PE

or 

KE=PE

300

T or F

A greater height for GPE translates to greater velocity for KE.

True

400

How much kinetic energy does a 30kg object have when sitting at 6m off the ground?

30 x 9.8 x 6 = 1764 J

MY MISTAKE

0 KE or 1764 J GPE

500

What is the velocity of a 500kg roller coaster at the bottom of a 100m drop?

PE = 500 x 9.8 x 100 = 490000 J

490000 J = 1/2 x 500 x v²

490000/250 = v² =1960

v = 44 m/s

Potential Energy

100

Equation for GPE

mgh

200

variable used for potential energy

U

300

Equation for elastic potential energy

1/2kx²

400

what type of energy is in springs and rubber bands

elastic potential energy

500

an object at 100m from the ground will have MORE or LESS GPE than one at 50m from the ground?

MORE

Kinetic Energy

100

what does kinetic mean?

moving/in motion

200

Equation for kinetic energy

1/2mv²

300

If the speed of an object doubles, how does its kinetic energy change?

4x

400

a roller coaster will have the most kinetic energy where?

bottom of tallest hill

500

How much kinetic energy would a 2000kg car have while traveling 10m/s?

100,000 J