m = 100 kg
v = 0
u = 30 m/s
s = 50 m
F = ?
W = ?
work done = [tex] \frac{1}{2} mv^2 - \frac{1}{2} mu^2[/tex]
= [tex] \frac{1}{2} *100 * (0)^2 - \frac{1}{2} * 100 * (30)^2[/tex]
= [tex]50 * 0 - * 50 * 900
[/tex]
W = - 45000 J
[tex]W = F * S[/tex]
[tex] \frac{W}{S} = F[/tex]
[tex] \frac{-45000}{50} = F[/tex]
therefore, F = - 900N
