How can the energy efficiency for any energy transfer be calculated?
efficiency = useful out put energy trans f er
total in put energy trans f er
Efficiency may also be calculated using the equation:
efficiency = useful power out put
total power in put
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What is the equation for change in thermal energy?
change in thermal energy = mass × specific heat capacity
× temperature change
∆ E = m c ∆ θ
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What is gravity?
Weight is the force acting on an object due to gravity. The force of
gravity close to the Earth is due to the gravitational field around the
Earth.
The weight of an object depends on the gravitational field strength
at the point where the object is.
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What is the equation of gravity?
The weight of an object can be calculated using the equation:
weight = mass × gravitational field strength
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What is the equation for work done?
The work done by a force on an object can be calculated using the
equation:
work done = force × distance
moved along the line of action of the force
W = F s
work done, W, in joules, J
force, F, in newtons, N
distance, s, in metre
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What is the equation for force?
force = spring constant × extension
F = k e
force, F, in newtons, N
spring constant, k, in newtons per metre, N/m
extension, e, in metres, m
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What is the equation for
elastic potential energy?
elastic potential energy = 0.5 × s pring constant × extension 2
Ee
=
1
2
k e2
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What is the equation for
distance travelled?
distance travelled = s peed × time
s = v t
distance, s, in metres, m
speed, v, in metres per second, m/s
time, t, in seconds, s
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What is velocity?
The velocity of an object is its speed in a given direction. Velocity is
a vector quantity.
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Other cards in this set
Card 2
Front
What is the equation for change in thermal energy?
Back
change in thermal energy = mass × specific heat capacity
× temperature change
∆ E = m c ∆ θ
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