A truck travelling due to north at `20m s^(-1)` turns west and travels at the same speed. Find the change in its velocity.

Options

A. 40 m/s N - W
B. `20sqrt(2)` m/s N - W
C. 40 m/s S - W
D. `20sqrt(2)` m/s S - W

Answer

4

Explanation

From figure

`bar(v)_(1)=20bar(j)and bar(v)_(2)=-20hat(i)`
`/_\bar(v)=bar(v)_(2)-bar(v)_(1)=20(hat(i)+hat(j))`
`|/_\bar(v)|=20sqrt(2)`and direction
`theta=tan^(-1)(1)=45^(@)i.e.`S-W