A body is moving with velocity `30 m//s` towards east. After `10 s` its velocity becomes `40 m//s` towards north. The average acceleration of the body is.

Options

A. `7ms^(-2)`
B. `sqrt(7)ms^(-2)`
C. `5ms^(-2)`
D. `1ms^(-2)`

Answer

C

Explanation

`overline(v_(i))=v_(1)hati,overline(v)_(f)=v_(2)hatj,Deltaoverline(v)=overline(v)_(f)-overline(v)_(i)=v_(2)hatj-v_(1)hati`
`|Deltaoverline(v)|=sqrt(v_(1)^(2)+v_(2)^(2)),a=|(Deltav)/(Deltat)|`