Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physics > Work And Power > Flashcards

Work And Power Flashcards

1
Q

Can energy be created or destroyed?

A

Energy can not be created or destroyed…
Only transferred

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

What’s a closed system?

A

A system which experiences no external forces

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

GPE=

A

GPE= MassXgravityXheight

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

Ke=

A

Ke= 1/2 X Mass X v^2

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

What’s work done ?
Calculation for work done?

A

-the measure of energy transfer when a force (F) moves an object through a distance (d)

-work done = force (n) X distance moved in direction of force (m)

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

Why do mechanical processes waste a lot of energy?

A

Because they get hot due to friction ,energy is dissipated as heat —> rise in temp

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

What’s power?
What’s the equation for power?

A

-power is the rate at which energy is transferred

-power (w) = work done(energy transferred) /time taken

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

Equation for efficiency =

A

Efficiency = useful output / total input energy

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

In power 1 w = …

A

In power 1 w = 1j per second

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

What effect does doubling speed have on ke?

A

Doubling speed quadruples ke

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

Work done is equal too?

A

Work done is equal to energy transferred

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

Non contact forces…

A

-Gravitational attraction

-electrostatic attraction / repulsion

-magnetic attraction / repulsion

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

Contact forces…

A

-normal contact force

-friction

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

Vector has…

A

Size and direction

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

Scalar has…

A

Just size

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

Force that act on a sky diver? How..

A

-Air resistance.
-Weight

-initially sky river has no air reisistance, only force acting on him is weight.
-as he falls he accelerates (increasing air resistance)
-therefore resultant force decreases
-eventually weight and air resistance balance out so there’s no resultant force and terminal velocity is reached

17
Q

Momentum of a force (newton meters) =

A

Momentum of a force (Nm) = force (N) X distance perpendicular to direction of force (M)

18
Q

When does equilibrium occur ?

A

sum of anti-clockwise moments = sum of clockwise moments

19
Q

What happens to the second gear when a gear supplying the force is connected to a second gear with fewer teeth?

A

Second gear will turn faster
With less force
In opposite direction

20
Q

What’s does lubricatiom do?

A

Reduces friction so reduces unwanted energy transfer . Increases efficiency

Physics (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions