since the speed decreases at 10 m/s every second,
v = 30 - 10t
after t seconds. Looks like it takes 3 seconds to stop. The distance traveled in t seconds is thus
s = 30t - 5t^2
You can use that to figure out (b) and (c)
A downhill skier crosses the finishing line at a speed of 30
1
ms
−
and immediately starts to
decelerate at 10 m s
−
2
. There is a barrier 50 metres beyond the finishing line.
(a) Find an expression for the skier’s speed when she is
V
metres beyond the finishing
line.
(b) How fast is she travelling when she is 40 metres beyond the finishing line?
(c) How far short of the barrier does she come to a stop?
1 answer