Question

Derive an expression for velocity of a projectile at any instant of time

Answer 1

Velocity = Ucos(Ф)i + (Usin(Ф)-g(t))j where, U=magnitude of initial velocity Ф=angle made with ground (X-axis) g=magnitude of acceleration i, j= unit vectors along X &Y axes t=instant of time after projection

Answer 2

Velocity = ucosФ i + usinФ-gt j
u = initial velocity 
Ф = angle of projection
g = acceleration for gravity
t = time taken