Work and Energy
Energy
Work and Power
Work--> Kinetic Energy
Work & Potential Energy
100
Define: Work
the change in energy of an object done by applying a Force to an object causing it to have displacement
100

What is an example when an object has gravitational potential energy

An apple hanging from a tree branch...

100

What are the SI units for power?

Watts

100
What is Kinetic Energy?
Energy of a moving object
100

What is potential energy.

Energy when an object is still.

200

What is the formula for work?

W=F(D) D=Distance, meters; F=Force, Newtons

200

A ball falling through the air has which 2 types of energy?

gravitational potential energy and kinetic energy

200
What is the difference between energy and power?
work and energy don't involve time, but power does
200
What is the formula for KE?
KE=1/2MV^2 (Joules)
200
Define gravitational potential energy?
Energy of an object placed at a height above a reference level
300

When is work done and not done during the lift of a military press?

When the object is being lifted, not at the top when it is still.

300

A pin ball being pushed into action by a spring. 

mechanical and kinetic (maybe gravitational too!)

300

What is the formula for power

P=W/T

300
Can KE ever be negative?
No, the velocity is squared-->always positive
300

What is the formula for gravitational potential energy?

PE=mgh

400

What is an example of when force is applied but no work is done? 

push on wall or other 

400

The ME of a coconut falling from a tree remains constant? (True/False)

True

400
Who does more work? Spencer walking up the 20 m high staircase carrying his backpack in 10 seconds, or John running up the same staircase carrying a backpack in 3 seconds?
Same height, so same work John feels more tired because used more power
400

Where is kinetic energy highest on our rollercoasters?

Towards the bottom when it is going fastest

400

An object has a mass of 250 kg. It is 20 m above the ground. What is the PE?

49,000J

500

1) How much work is done if I pushed a 100 N crate across the floor with a force of 50 N for a distance of 10 M? 2) How much work is done if Ethan pushes a force of 600 against the wall for 30 second?

1) W=F(D) 50N(10M)=500 J 2) NO WORK BECAUSE NOT MOVING

500

What is the law of conservation of energy.

Energy is never created, lost, or destroyed. Only transformed.

500

A runner runs up a flight of stairs using 200J of work in 10 sec

Power: P=W/T= 20 Watts

500

List 1 reason why work and energy are related.

1. They have the same labels.

2. They are interchangeable or directly proportional.

500
A 45 kg skier starts off from rest at the top of the hill 85 m high. How much PEG does the skier have at the top?
PE=mgh =60Kg(10m/s^2)(10m)
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