11797032
Description
Mind Map by Kieran Lancaster, updated more than 1 year ago
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Created by Kieran Lancaster
over 6 years ago
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Chapter 5 - Work, Energy and Power
- Work done and energy
- Work done (Units Nm/J) = Force X distance moved in the direction of the force
- Work done = Energy transferred (Energy is
the capacity to do work)
- W=Fx
- Work done = Energy transferred (Energy is
the capacity to do work)
- When force is applied at an angle, the following
formula can be used
- Work done (Units Nm/J) = Force X distance moved in the direction of the force
- Conservation of energy
- Energy is the capacity for doing work
- "Potential" energy can be stored, and converted into other
forms. This includes G.P.E, elastic and electric. Non
potential energy can only be transferred
- Principle of conservation of energy - The total energy of a closed system remains constant,
energy can never be created or destroyed, only transferred from one form to another
- Energy is the capacity for doing work
- K.E and G.P.E
- K.E is directly proportional to the mass of the object,
and directly proportional to the speed squared
- Gravitational Potential energy - The capacity for doing work
as a result of an objects position in a gravitational field
- This formula can only be used for a
UNIFORM gravitational field (i.e close
to Earth's surface) where g can be
assumed to remain constant
- It is gained with height
- Using the idea of W=Fd, the force is Weight
(mg), and the distance is the vertical height
travelled (h), meaning you get G.P.E = mgh
- It is gained with height
- G.P.E can be converted to K.E, e.g with a waterfall or
rollercoaster. By putting them equal to each other, the
final velocity v does not depend on the mass of the
object. It's only true if there are no resistive forces
- This formula can only be used for a
UNIFORM gravitational field (i.e close
to Earth's surface) where g can be
assumed to remain constant
- K.E is directly proportional to the mass of the object,
and directly proportional to the speed squared
- Power and efficiency
- Power is the rate of work done (Or rate of
energy transfer). Units are Js^-1, or Watts
- Sometimes, a constant force has to be exerted
to maintain speed, e.g a car on a road.
- For the car, the net force is zero, since the
power of the engine is equal to the rate of
work done against frictional forces
- This equation can be used for a
variety of situations, like above
- This equation can be used for a
variety of situations, like above
- For the car, the net force is zero, since the
power of the engine is equal to the rate of
work done against frictional forces
- All energy in a closed system is conserved, but it does not mean
all energy is converted into useful output energy
- Power is the rate of work done (Or rate of
energy transfer). Units are Js^-1, or Watts
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