An object experiences a constant acceleration of 4.0 m/s2 along the −x axis for 4s, obtaining a velocity of 31 m/s in a direction 30° from the +x axis. Find the initial velocity vector of the object. (The angle of the object is measured counterclockwise from the +x-axis.)

Answer 1

V = Vo + a*t = 31m/s[30o]
Vo - 4*4 = 31*Cos 30 + i31*sin 30
Vo - 16 = 26.8 + 15.5i
Vo = 42.8 + 15.5i

Tan A = Y/X = 15.5/42.8 = 0.36215
A = 19.91o

Vo = 42.8/Cos 19.91 = 45.5m/s[19.9o] =
Initial velocity.