a motor car is going due north at a speed of 50 km/h.it makes a 90^{ o } ** left turn without changin its speed the change in velocity of the car is ? **

(The bold letters represent vector quantities)

Initial velocity of the car is, **v _{1}** = 50 km/h towards north.

Final velocity of the car is, **v _{2}** = 50 km/h towards west.

Change in velocity, **∆v** = **v _{2}** –

**v**

_{1}Magnitude of the change is,

|∆v| = (v_{2}^{2} + v_{1}^{2} – 2 v_{1} v_{2} cos90^{0})^{1/2} = 70.71 km/h

The direction of this change is **φ** * w.r.t the initial direction*,

tan^{-1} (v_{2})/(-v_{1})

= tan^{-1} (-1)

**= 135**^{0}

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