Cars on Ramps by iUrt26i


									Cars on Ramps

   The Science behind why Things
The Car is at the top of the ramp. It has
potential energy. It is not moving yet.
The Car has started moving.
Some of its potential energy
has turned into kinetic
The Car is at the middle of the ramp.
Half of its potential energy has become
kinetic energy.
The Car continues down the ramp.
More of its potential energy is turned
into kinetic energy.
The Car is at the bottom of the ramp. It
has kinetic energy only. It has not
stopped moving yet.
 Gravity makes things fall
 The acceleration due to Gravity on earth
  is 10 m/s/s

 Ifyou lift something up (eg a ramp or
  car), you do not change the gravity!
What does change then?
 Gravity  doesn’t change (unless you go
  to a different planet!)
 So what makes something fall faster
  when it starts off higher?
 Energy
 The higher up something is, the further
  it can fall. We say it has Potential
    Gravitational Potential Energy
 P.E. = mass x g x height to fall
 P.E. = mgh
 What units are all these measured in?
 PE is Joules, mass is kg, height is metres.
 The higher up the car starts (or the heavier it
  is), the more potential energy it has.
 Once it starts moving, the potential energy
  gradually changes to kinetic energy as it falls
 Some energy may be lost as sound or heat
  energy due to friction in the wheels, etc.
Kinetic Energy
 K.E. = (mass x velocity x velocity)/2
 K.E. = ½ mv2

 The more potential energy the car starts
 with, the more kinetic energy it will gain
 and therefore the faster it will travel
 down the ramp.
What could you change? (The
‘Independent Variable’)
 Height of the ramp
 Angle of the ramp
 Mass of the car
 Surface of the ramp/floor
 Force applied to the car (mass on a pulley)
 The car
 Starting point on the ramp
What could you measure?
(The ‘Dependant Variable’)
 Speed  of the car
 Distance travelled off the ramp
 Time taken
 Acceleration

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