Brainscape's Knowledge GenomeTM

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


See full index

Physics 71 > Potential Energy and Energy Conservation > Flashcards

Potential Energy and Energy Conservation Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

Capacity to do work

A

Energy

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

Energy transferred to the object by applying a force along a displacement

A

Work

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

Unit for Work

A

Joule

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

Energy stores in an object associated with position; scalar quantity; possibility for work to be done

A

Potential Energy

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

Is Potential Energy a property of a single object?

A

No. It is a property of interacting systems.

e.g. ball-earth system, block-spring system

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

T or F. There is more potential for work to be done on the person by the gravitational force.

A

T

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

Potential energy associated with a body’s weight and its height above the ground

A

Gravitational Potential Energy

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

Two ways to describe freely falling bodies

A
  1. Force of gravity does work on the body so KE increases
  2. GPE decreases as KE increases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What happens when a block is raised to a height?

A

Negative Work by weight → storing of energy into GPE

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

What happens when a block falls from a height?

A

Positive Work by weight → change in Kinetic Energy

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

How to solve for GPE, U_grav

A

U_grav = mgy

product of weight mg and height y above the origin of coordinates

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

Formula when raising an object to a height y_2

A

W_grav = -ΔU_grav

this holds true in both cases if the body is moving upwards or falling

the negative (-) sign is essential

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

W if the body moves up

A

negative

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

W if the body moves down

A

positive

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

Formula/equation for conservation of ME if gravity is the only force acting on the object

A

1/2mv1^2 + mgy1 = 1/2mv2^2 + mgy2

numbers after v and y are subscript

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

What is the total mechanical energy of a system (E)?

A

sum of kinetic and potenetial energy

E = K + U_grav

17
Q

“system” – ________ + ________

A

“system” – body + earth

18
Q

When only the force of gravity does work, the total mechanical energy is ________, i.e. conserved

A

constant

ΔE_mechanical = 0

19
Q

A quantity that always has the same value

A

“conserved”

20
Q

ΔK and ΔU_grav of a ball thrown up

A

ΔK < 0 ; ΔU_grav > 0

21
Q

ΔK and ΔU_grav of a ball dropped

A

ΔK > 0 ; ΔU_grav < 0

22
Q

A body that can return to its original shape and size after being deformed

A

“elastic”

23
Q

Basis of formula for elastic potential energy

A

Newton’s Third Law

For every action (force) there is an equal and opposite reaction

24
Q

Formula/equation for work done on a spring

A

W = 1/2kx2^2 - 1/2kx1^2

numbers beside x are subscripts

25
Q

Formula/equation for work done by a spring

A

W_el = 1/2kx1^2 - 1/2kx2^2

numbers beside x are subscripts

26
Q

Work done by the spring can be defined in terms of ______________.

A

elastic potential energy

27
Q

In a spring system, what is always the position where the spring is neither stretched nor compressed?

A

x = 0

In a spring system, x = 0 is always the position where the spring is neither stretched nor compressed.

28
Q

Formula for elastic potential energy

A

U_el = 1/2kx^2

29
Q

W_el formula

A

W_el = ΔU_el

30
Q

value of W_el as the spring stretches

A

negative

31
Q

value of W_el as the spring relaxes

A

positive

32
Q

T or F. The work done by the spring can be defined in terms of elastic potential energy.

A

T. Formula is K_1 + U_el,1 = K_2 + U_el,2

33
Q

Force that offers a two-way conversion between kinetic and potential energy

A

Conservative force

34
Q

Examples of conservative force

A
  • Gravitational Force
  • Force due to a spring
35
Q

Force that doesn’t have a two-way conversion between kinetic and potential energy

A

Non-conservative force

36
Q

Examples of non-conservative force

A
  • Friction force
  • Force due to fluid resistance
37
Q

Characteristics of a conservative force

A
  • path-independent
  • reversible
  • when starting and ending points are the same, total work is zero
38
Q

Characteristics of a non-conservative force

A
  • path-dependent
  • irreversible
  • when starting and ending points are the same, total work is NOT zero
39
Q

Energy associated with the change in the state of the materials

A

internal energy

ΔK + ΔU + ΔU_int = 0

KE, PE, and internal energy of a system may all change but the sum of those changes is always zero.

Physics 71 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions