A particle has an initial velocity `(2 hat(i) + 3 hat(j))` and an accelaration `(0.3 hat(i) + 0.2 hat(j))`. The magnitude of velocity after `10 s` will be

Options

A. `9sqrt(2) units`
B. `5sqrtunits`
C. `5 units`
D. `9 units`

Answer

B

Explanation

`vec(u) = 2 hat(i) + 3 hat(j) = u_(x) hat(i) + u_(y) hat(j)`
`vec(a) = 0.3 hat(i) + 0.2 hat(j) = a_(x) hat(i) + a_(y) hat(j)`
`v_(x) = u_(x) + a_(x) t = 2 + 0.3 xx 10 = 5`
`v_(y) = u_(y) + a_(y) t = 3 + 0.2 xx 10 = 5`
`v = sqrt(v_(x)^(2) + v_(y)^(2)) = 5sqrt(2)`