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. `1 m//s^2`
B. `7 m//s^2`
C. `sqrt7 m//s^2`
D. `5 m//s^2`

Answer

D

Explanation

Velocity towards east direction `vecv_(1) = 30 hatim//s`
Velocity towards north direction , `vec_(2) = 40 hatj m//s`
Change in velocity , `Deltavecv = vecv_(2) - vecv_(1) = (40 hatj - 30 hati)`
`:.|Deltavecv|=|40hatj-30hati|=50 m//s`
Average acceleration , `veca_(av) = ("Change in velocity ")/("Time interval")`
`veca_(av)=(vecv_2-vecv_1)/(Deltat)=(Deltavecv)/(Deltat)`
`|veca_(av)|=(|Deltavecv|)/(Deltat)=(50m//s)/(10s) = 5m//s^2`