a) Quantities

a) displacement, instantaneous speed, average speed, velocity, and acceleration

speed and distance are scalar quantities

• distance = the length between two points

• speed = the distance travelled by an object per second

• v = ∆x/∆t

  • average speed (ms^-1) = change in distance (m) / change in time (s)

to calculate instantaneous speed from a distance-time graph (ms^-1)

• draw a tangent to the distance-time graph at the given time

• calculate the gradient of the tangent using rise/run

velocity and displacement are vector quantities

• displacement = the shortest distance between two points

• velocity = the displacement and direction travelled by an object per second

• v = ∆s/∆t

  • average velocity (ms^-1) = change in displacement (m) / change in time (s)

acceleration is a vector quantity

• acceleration = the rate of change of velocity

• a = ∆v/∆t

  • acceleration (ms^-2) = change in velocity (ms^-1) / change in time (s)