A ball is moving in a circular path of radius 5m . If tangential acceleration at any instant is `10 ms^(-1)` and the net acceleration , then the instantaneous speed is

Options

A. `50 sqrt(3) ms^(-1)`
B. `9.3 ms^(-1)`
C. `6.6 ms^(-1)`
D. `5.4 ms^(-1)`

Answer

B

Explanation

From relation `tan theta = (a_(t))/(a_(c)) = (a_(t)r)/(v^(2)) " "[because a_(c) = (v^(2))/(r)]`
`v^(2) = (a_(t)r)/(tan theta) = (10 xx 5)/(tan 30^(@)) = 50 sqrt(2)`
`v^(2) = 50 xx 1.732 = 86.6`
`therefore " "v= sqrt(86.6) = 9.3 ms^(-1)`