P2

P2

1. Speed and velocity

   • Speed= How fast you are going e.g 30mph
   • Velocity= speed with a direction specified e.g 30mph north

2. Distance + Time graphs

   • Steeper curve = Speeding up
   • Curves
     • Up = Acceleration
     • Down = Deceleration
   • Calculating
     • Speed = Gradient = vertical/horizontal
       • e.g 500/30 (use scales NOT cm) = 16.7m/s
       • change in distance/change in time
   • Steeper = Faster
   • Straight = Steady speed
   • Levelling = Slowing down
   • Flat = Stationary
   • Gradient = Speed
   • Downhill = Back to starting point

3. Acceleration

   • Define
     • How quickly the velocity is changing.
       • Change in velocity: change in speed or change in direction or both
   • Change in velocity/time taken
     • (v-u)/(axt)
       • v-u= change in velocity
       • a= acceleration = m/s2

4. Velocity-time graph

   • Gradient = Aceleration
   • Curve = changing acceleration
   • Flat sections = steady speed
   • Steeper = greater the acceleration/deceleration
   • Uphill = Acceleration
   • Downhill = Deceleration
   • Area under any section is equal to the distance travelled in that time period.
   • Acceleration = Gradient = vertical change/horizontal change
     • e.g 30/20 = 1.5m/s2

5. Gravitational force

   • Rule: Attracts all masses
   • Effects
     • 1. On a planet makes all things accelerate towards the ground, with the same acceleration. (10m/s2 on Earth)
     • 2. Gives everything a weight

6. Weight and mass

   • Mass = amount of stuff in an object
   • Weight = Pull of gravitational force causes weight