Question

What are the magnitude Δυ and angle θ of the change in velocity if the initial velocity is 90.0 m/s south and the final velocity is 85.0 m/s west? Let the angle θ be measured relative to the east direction (e.g., θ = 90' means Δύ points north, θ 180。 means Δν points west, etc.). Δυ- 123.79 m/s

Answer 1

Let us assume that the East is +x axis and North is +y axis,

therefore

and

Final velocity

Now,

the change in the velocity is

Δι -85i

which gives us

The magnitude of the given velocity is

which gives us

Now, the direction of the velocity is given by

which gives us

or

Hence,

The angle w.r.t the East direction of from +x axis is