A particle is moving east-wards with a velocity of 5m/s. in 10 seconds the velocity changes to 5 m/s northwards.What is the average acceleration in this time ?
Initial velocity, u = 5 m/s due east
Final velocity, v = 5 m/s due north
Change in velocity, Δv = v – u = 5 m/s due north - 5 m/s due east
=> Δv = 5 m/s due north + 5 m/s due west [negative of east direction is west]
Δv = (v2 + u2)1/2
=> Δv = 5√2 m/s
Direction of Δv is given by,
tanθ = v/u = -1
=> θ = -45o
Thus, the acceleration is a = Δv/t = 5√2/10 = 1/√2 m/s2 and is directed towards North-West direction.