PE/KE/Work/Simple Machines/MA/ME

Potential Energy

100

stored energy

Potential Energy

200

What is the equation to calculate GPE?

GPE=mgh

300

Sarah is trying to calculate GPE. What is wrong with the known variables she collected below?

m=25g

h= 2m

g= 9.8 N/kg

mass should be in kilograms

400

Gravitational potential energy depends on the ________ and ________ of the object.

mass and height

500

A type of energy that is stored when stretching a rubber band.

Elastic potential energy

Kinetic Energy

100

Energy due to motion.

Kinetic Energy

200

The  faster an object moves, the (more/less) KE it has.

more

300

An object with more mass will have (more/less) KE than object with less mass.

more

400

A marble with a mass of 12 kg increases speed from 2m/s to 3.5 m/s. Calculate the marble's change in kinetic energy.

Nearest tenth.

49.5J

KE2-KE1

1/2(12kg)(3.5m/s)²- 1/2(12kg)(2m/s)²

500

Name the correct units on:

Kinetic energy

mass

speed

KE= J

mass= kg

speed= m/s

Law of Conservation of Energy

100

States that energy CANNOT BE created nor destroyed.

Law of Conservation of Energy

200

A pendulum swings back and forth. At what point will the pendulum have the greatest KE. 

A. Away from the ground

B. Near the ground

B. Near the ground

300

True/False:

A roller coaster slows down because energy disappears.

False

400

Anything around which you can imagine a boundary.

system

500

The total potential energy and kinetic energy in a system.

Mechanical Energy

Work/Simple Machines/MA/ME

100

Force must be _______ to the direction in which an object travels in order for work to be done.

Parallel

200

What is the equation for work?

W= fd

300

An axe is an example of which simple machine?

Wedge

400

d= 20m

W= 7.8 J

F=?

correct units! Round to nearest whole number

156 N

F=Wd

F=7.8J x 20m

500

How do machines change the way work is done(make work easier)?

[HINT: 3 ways]

Increase speed

change direction of force

increase force

Calculations

100

Mass= 29 kg

Height= 24 m

GPE= ???

Nearest whole number

6821J

GPE= mgh

29 x 9.8 x 24

200

Output Force = 250N

Input Force= 125 N

MA=??

MA= 2

Output F/ Input F= 250/125

300

m= 28kg

v= 12 m/s

KE=???

nearest whole number

2016J

KE= 1/2mv² = 1/2(28)(12)²

400

You do 15 J of work in pushing a box up a ramp. The output work from the inclined plane is 8J. What is the efficiency of the inclined plane?

nearest whole number

53%

Wout/Win x 100= 8J/15J x 100= 53.3= 53

500

Mass= 8 kg

distance= 12m

W=???

nearest whole number. give me units!!!

941 J

First: Convert kg to N(we need a force for this equation). 

F=ma = 8kg x 9.8m/s² =78.4N

Second: Use W=Fxd with force above.

W= 78.4N x 12m = 940.8 J