Movement and position

1.1 Units: kg, m, m/s, m/s2, N, s, N/kg


a) Movement and position
1.2 understand and use distance-time graphs


Distance -time graphs


The gradient of a distance-time graph=speed
s=d/t

Distance isn't increasing-gradient=0, hence speed=0---->object is stationary (not moving)

The steeper the graph, the greater the speed as the gradient is steeper. 

If the graph is curved, then the speed must be changing. If it is curving upwards (blue line), the speed is increasing, if it is curving downwards, the speed is decreasing. So the gradient of the graph also tells us how the speed is changing.

Instantaneous speed=How fast an object is moving at a particular instant.

The gradient of the tangent at a point on the distance-time graph gives us the instantaneous speed.

1.3 recall and use the relationship between average speed, distance moved and time:

average speed=distance moved/time taken

s=d/t

1.4 recall and use the relationship between acceleration, velocity and time:

acceleration=change in velocity/time taken

a=(v-u)/t

where v=final velocity

          u=initial velocity

          t=time 

1.5 interpret velocity-time graphs

1.6 determine acceleration from the gradient of a velocity-time graph

the gradient at a point on the velocity-time graph gives you the acceleration

1.7 determine the distance travelled from the area between a velocity-time graph and the time axis

basically, the area under a velocity time graph = distance travelled