OCR mechanics

1a)
Similarity and difference between velocity and speed.
Both have a unit of ms^-1          ,       Velocity has a direction where as speed does not.

1b)
Circle track with a radius of 0.60m completes a full circuit in 12s, find the speed.
Distance = 2 x  pie x 0.6         =  3.8m
3.8/12 =0.32 ms^-2

1c)
What is the total displacement of the locomotive after a quarter of the track.
0.6^2 + 0.6^2 = 0.72m
Sqroot of 0.72 = 0.85m

1d)
The locomotive travels at a constant speed why is the velocity always changing
This is because velocity is calculated using displacement which has a direction so velocity also has a direction meaning the velocity changes as the direction changes