Forces and their effects

Forces and their effects

1. Speed and velocity are both how fast you're going

   • Speed is just how fast you're going (eg. 30 mph or 20m/s) with no regard to the direction.
   • Velocity however must also have the direction specified eg. 30 mph north or 20m/s, 060degrees.
   • Speed = distance/time

2. Distance time graphs

   • 1) gradient=speed.
   • 2) flat sections are where it's stationary.
   • 3) straight uphill or downhill sections mean it is traveling at a steady speed.
   • 4) the steeper the graph the faster its going.
   • 5) downhill sections mean its going back toward its starting point.
   • 6) curves represent acceleration or deceleration.
   • 7) a steepening curve means its speading up (increasing gradient)
   • 8) a leveling off curve means its slowing down (decreasing gradient).
   • Calculating speed - is just the gradient
     • Speed = gradient =
     • vertical --------- horizontal
     • =
     • 500 ----- 30
     • =
     • 16.7m/s

3. Acceleration and velocity-time graphs

   • Acceleration is how quickly velocity is changing
   • Acceleration =
     • Change in velocity ------------------- Time Taken
   • (v - u) --------- a X t
     • v = final velocity and u = the initial velocity.
   • 1) gradient = acceleration.
   • 2) flat sections represent steady speed.
   • 3) the steeper the graph, the greater the acceleration or delceleration.
   • 4) uphill sections (/) are acceleration.
   • 5) downhill sections (\) are deceleration.
   • 6) the area under any section of the graph is equal to the distance travelled in that time interval.
   • 7) a curve means changing acceleration.
   • Calculating acceleration, velocity and distance from the graph
     • 1) the acceleration represented by the first section of the graph is :
       • Acceleration =
         • gradient =
           • vertical change ---------------- horizontal change
             • 30 ---- 20
               • = 1.5 m/s2
             • =
     • 2) the velocity at any point can be simply found by reading the value off the velocity axis.
     • 3) the distance travelled in any time interval is equal to the area under the graph.

4. Weight, mass and gravity

5. Forces and acceleration