work, power and energy Flashcards

1
Q

work

A
when a force acts on a body, 
work done by the force is equal to
magnitude x distance the body moves
W = Fd
(N)(m)
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2
Q

joule

A

N.m

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3
Q

positive work

negative

A

force in the same direction, body moves

opposite

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4
Q

concentric

muscular work

A

positive work

W = tensile force x distance the muscles stretches

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5
Q

power

A

rate at which at work is performed

P(ower developed) = W/t

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6
Q

watts

A

N.m/s

1 horsepower = 746 watts

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7
Q

energy

A

capacity to do work

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8
Q

mechanical

theres 3 types

A

kinetic
potential
strain

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9
Q

kinetic

A

energy bc of its motion
KE = 1/2 x mass x (velocity)squared

is used to deform an object to create strain energy + heat

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10
Q

potential energy

A

position in relation to earths surface
stored energy
gravitational energy
PE = weight x height above surface

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11
Q

strain energy

A

capaicty to do work while if reforms after being deformed
elastic potential energy
stored energy
SE = 1/2 x k(a spring constant) x x(distance over which the material is deformed)

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12
Q

law of conservation of mechanical energy

A

is constant when gravity is the only external force

PE + KE + SE = C

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13
Q

work

A

= change in KE + change in PE + change TE

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