Scientists often make measurements. The physical quantities they measure fall into two categories: scalars and vectors. Scalar and vector quantities are treated differently in calculations.
Part ofCombined ScienceMotion
Find the distance travelled by Caitlyn if she sprints at an average speed of 9 m/s for 4 seconds.
d = s × t
Distance moved = 9 m/s × 4 s = 36 m
The distance travelled by Caitlyn is 36 m.
Find the time taken to cover 256 m at an average speed of 8 m/s.
t = d ÷ s
Time = 256 m ÷ 8 m/s = 32 s.
The time taken is 32 s.
Find the velocity of a train if it covers 1000 metres in a south direction in 25 seconds.
v = displacement ÷ time
The displacement = 1000 m south
Velocity v = 1000 m ÷ 25 s = 40 m/s south. Don’t forget the direction!
The velocity of the train is 40 m/s south.
