A bus is moving on a straight road towards north with a uniform speed of 50 `km//hour` turns through `90^(@)`. If the speed remains unchanged after turning, the increase in the velocity of bus in the turning process is

Options

A. 70.7 km/hour along south-west direction
B. zero
C. 50 km/hour along west
D. 70.7 km/hour along north-west direction.

Answer

A

Explanation

`vecv_1`=50 km `h^(-1)` due North ,
`vecv_2`=50 km `h^(-1)` due West .
Angle between `vecv_1` and `vecv_2=90^@`
`-vecv_1`=50 km `h^(-1)` due South
`therefore` Change in velocity = `|vecv_2-vecv_1|=|vecv_2+(-vecv_1)|`
`=sqrt(v_2^2+v_1^2) = sqrt(50^2+50^2)`= 70.7 km/h