P2 1 Motion

P2 1 Motion

1. Distance-time graphs

   • The distance-time graph for a stationary object is a horizontal line
   • The distance-time graph for an object moving at a constant speed is a straight line that slopes upwards
   • The gradient of a distance-time graph represents the object's speed
     • The steeper the line, the faster the object's speed

2. Velocity and acceleration

   • Velocity is speed IN A GIVEN DIRECTION
   • Acceleration is change in velocity per second
     • Maths for P2
     • Acceleration therefore means change in speed OR CHANGE IN DIRECTION
     • The unit of acceleration is metres per second squared
   • Deceleration is the change of velocity per second when an object slows down
     • If the result of an acceleration calculation is negative, it means the object is deceleratiing (slowing down)

3. Velocity -time graphs

   • If a velocity-time graph is a horizontal line, the velocity is constant so the acceleration is zero
   • The gradient of a velocity-time graph represents the acceleration
     • The steeper the line, the faster the object's acceleration
     • A downward sloping line means the object is decelerating (slowing down)
   • The area under the line on a velocity-time graph represents the distance travelled

4. See notes for maths

   • Maths for P2