physics
posted by Sam .
A luge and its rider, with a total mass of 84 kg, emerge from a downhill track onto a horizontal straight track with an initial speed of 41 m/s. Assume that they stop with a constant deceleration of 3.5 m/s2.
(a) What magnitude F is required for the decelerating force?
(b) What distance d do they travel while decelerating?
(c) What work W is done on them by the decelerating force?
(d) What is F for a deceleration of 7.0 m/s2?
(e) What is d for a deceleration of 7.0 m/s2?
(f) What is W for a deceleration of 7.0 m/s2?

F= ma
Vf^2=Vi^2 + 2ad solve for d.
Work = F*d 
a) F = ma
F = 84kg*3.5m/s^2
b)v=0
x= (41m/s)^2/(2(3.5m/s^2))
c)W is going in the x direction because it's decelerating
W= Fd
Then you just apply these equations to d,e, and f.