Chapter 6 - Work, Energy and Power Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Define “energy”

A

The capacity to do work

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the SI unit for energy?

A

joule (J)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Energy is a ________ (scalar/vector) quantity

A

scalar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are some forms of non-potential energy?

A

kinetic energy, light energy, sound energy, electrical energy, thermal energy, nuclear energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are some forms of potential energy?

A

gravitational potential energy, elastic potential energy, chemical potential energy, magnetic potential energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Energy can be ________ from one form to another

A

converted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Define “kinetic energy”

A

The energy a body possesses due to its motion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Formula to calculate kinetic energy

A

K.E. = 1/2mv^2

[ kinetic energy = 1/2 x mass x velocity ]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Define “gravitational potential energy”

A

The energy a body possesses because of its position relative to the ground

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Formula to calculate gravitational potential energy

A

G.P.E. = mgh

[ gravitational potential energy = mass x height x gravitational field strength ]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

State the principle of conservation of energy

A

Energy cannot be created or destroyed, but only changes from one form to another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The total amount of energy in the universe is ________

A

always the same

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Define “work done”

A

The amount of energy that has been converted from one form to another or transferred from one body to another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the SI unit for work?

A

joule (J)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Work is a ________ (scalar/vector) quantity

A

scalar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Formula to calculate work done

A

W = F x d

[ work done = force x distance moved in the direction of the force ]

17
Q

Define “power”

A

The rate of doing work

or: the rate at which energy changes of one form to another

18
Q

Formula to calculate power

A

Power = W/t = ΔE/t

[ power = work done/time taken = energy change/time taken ]

19
Q

What is the SI unit for power?

A

watt (W)

20
Q

1 W = 1 ____

A

J s^-1

21
Q

Define “efficiency”

A

The ratio of the useful energy output to the total energy input

22
Q

Efficiency is usually expressed as ________

A

a percentage

23
Q

Formula to calculate efficiency

A

Efficiency = (useful energy output/total energy input) x 100%

24
Q

Since useful energy output ________ than the total energy input, the efficiency of a system ________

A

cannot be greater

cannot be greater than 100%