Zusammenfassung der Ressource
P4 - Explaining Motion
- Speed
- Speed (m/s) =
Distance Traveled (m)
/ Time Taken (s)
- Distance (m) =
Speed (m/s) X
Time Taken (s)
- Time (s) = Distance (m) / Speed (m/s)
- Distance-Time Graphs
- Gradient = Speed
- Flat sections are where it's stationary
- The steeper the gradient, the faster it is going
- Straight lines meaning the object is moving at a constant
speed
- A steeping curve = Acceleration
- A leveling off curve = Deceleration
- Speed = Gradient = Vertical / Horizontal
- Displacement-Time Graphs
- Displacement can be
Positive or Negative
- They show is two different objects
travelling different directions from a point
- Acceleration
- Acceleration (m/s~2) =
Change in Velocity (m/s) /
Time Taken (s)
- Change in Velocity (m/s) =
Acceleration (m/s~2) X
Time Taken (s)
- Time Taken (s) =
Change in Velocity
(m/s) / Acceleration
(m/s~2)
- Velocity-Time Graphs
- Gradient = Acceleration
- Flat sections = Constant Speed
- The steeper the gradient,
the greater the acceleration
or deceleration
- Uphill sections are acceleration
- Downhill sections are deceleration
- Negative Velocity means
the object is travelling in the
opposite direction
- Forces and Friction
- Forces occur when
two object interact
- An object resting on a surface
experiences a reaction force
- Moving objects normally experience friction
- Three types of Friction
- Friction between solid surfaces which are gripping
- Friction between solid surfaces
which are sliding past each
other
- Can be reduced by adding a lubricant
- Resistance or
"Drag" from fluids
- Acceleration
- When a car exerts a bigger driving
force than the drag counter force,
the car will then accelerate.
- The bigger the force, the greater
the acceleration
- Momentum
- Momentum (kg m/s)
= Mass (kg) X
Velocity (m/s)
- Velocity (m/s) =
Momentum (kg m/s) /
Mass (kg)
- Mass (kg) =
Momentum (kg m/s) /
Velocity (m/s)
- Change of Momentum
- Change of Momentum (kg m/s) =
Resultant Force (N) x Time for which
the force acts (s)
- Resultant Force (N) =
Change of Momentum (kg
m/s) / Time for which the force
acts (s)
- Time for which the force acts (s)
= Change of Momentum (kg m/s)
/ Resultant Force (N)
- Car Safety Features Reduce Forces
- Crumple Zones
- Increases the time
taken for the car to stop
- Air Bags
- Slows the passenger
more gradually
- Seat Belts
- Increases the time taken for the
wearer to stop (reduces the forces
acting on the chest)
- Helmets
- Increases the time taken for your head to
come to a stop if it hits something hard
- Work
- When a force moves an object,
it does work and energy is
transferred to the object
- Amount of energy
transferred (J) =
Work Done (J)
- Work done by a force
- Work done by a force (J) = Force (N) x
Distance moved in direction of force (m)
- Force (J) = Work done by a force (J) /
Distance moved in direction of force (m)
- Distance moved in direction of force
(m) = Work done by a force (J) / Force
(N)
- Kinetic Energy
- Kinetic Energy (J) =
1/2 x Mass (kg) x
Velocity~2 ([m/s]~2)
- Mass (kg) =
1/2 x Kinetic
Energy (J) /
Velocity~2
([m/s]~2)
- Velocity~2 ([m/s]~2)
= 1/2 x Kinetic
Energy (J) / Mass (kg)
- GPE
- Change in GPE
- Change in GPE (J) = Weight (N) x Vertical Height Difference (m)
- Weight (N) = Change in GPE (J)
/ Vertical Height Difference (m)
- Vertical Height Difference (m)
= Change in GPE (J) / Weight
(N)
- Kinetic Energy Gained - GPE Lost