chapter 5 - work energy power Flashcards

1
Q

work done =

A

Force x distance traveled in the direction of the force = Fs
= energy transferred
Nm or J = kgm^2s^-2

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2
Q

work done at an angle

A

= Fs cosθ
where θ is the angle between the force and motion

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3
Q

energy

A

the capacity of one object/ system to do work
J
= work done

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4
Q

perpetual motion

A

a device in which once started will continue to move and do work without any further input of energy
this is impossible according the principle of conservation of energy

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5
Q

area under force distance graph

A

work done

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6
Q

principle of conservation of energy

A

the energy in a closed system always remains constant
energy can never be created or destroyed only transferred

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7
Q

forms of energy (9)

A
  • kinetic
  • GPE
  • chemical
  • elastic potential
  • electrical potential
  • nuclear
  • radiant
  • sound
  • thermal
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8
Q

kinetic energy

A
  • due to motion
    = 1/2mv^2
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9
Q

GPE

A

due to the position of a mass in a UNIFORM graviattional field
= mgh

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10
Q

chemical

A

energy due to bonds between atoms in a substance

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11
Q

elastic potential

A

due to a reversible change in shape of an object

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12
Q

electrical potential

A

due to the position of charge in an electrical field

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13
Q

nuclear

A

due to forces between protons and neutrons in an atom

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14
Q

radiant

A

energy due to EM waves

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15
Q

sound

A

energy due to mecgnaical wave motion of atoms

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16
Q

thermal

A

energy due to randomly distributed potential and kinetic energies of atoms within a system

17
Q

KE is proportional to

A

v^2
m

18
Q

energy exchange (KE and GPE)

A

mgh = 1/2 mv^2
v = root(2gh)

19
Q

effect of friction on a moving object

A

transfers KE to thermal energy

20
Q

power

A

rate of work done or energy transfered
= WD/t = Fv
Watts or J/s or kgm^2s^-3

21
Q

efficiency

A

useful energy output/ total energy input *100