Answer:
we got time and velocity over time.
so the distance is again the area underneath the graph
for a triangle with known base and height it's
4*10 / 2
distance traveled is 20
deceleration occurs when velocity decreases. that happens from t=2 till t=4
in 2 time-units we loose 10 units of velocity, so we decelerate by 5 units per 1 time
a (from t=2 to t=4) = -5v/t
