If a force of 15.0 N directed east acts on a stationary 5.00 kg mass, what are its acceleration, displacement, and velocity after 10.0 s?

2 answers

a. T = ma,
a = F/m = 15 / 5 = 3m/s^2.

b. D = V0*t + 0.5a*t^2,
D = 0 + 1.5*10^2 = 150m.

Vf = Vo + at,
Vf = 0 + 3*10 = 30m/s.
Where does 0.5 comes from?