Answer:
-50 N
Explanation:
Givens:
V_i = 36 km/h
V_f = 18 km/h
t = 2 s
m = 20 kg
First we have to convert our km/h into m/s:
(36 km*(1000 m/1 km)) / (60 min *(60 s/1 min)) = 10 m/s
(18 km*(1000 m/1 km)) / (60 min *(60 s/1 min)) = 5 m/s
a = (V_f - V_i)/t
a = (5 m/s - 10 m/s) / 2 s
a = -2.5 m/s^2
F = m(a)
F = 20 kg(-2.5 m/s^2)
F = -50 N
It's a negative force meaning its acting on it opposite its current direction of movement.
