A samll object of mass 10.0 g is at rest 30.0 cm from a horizontal disk's centre. The disk starts to rotate from rest about its centre with a constant angular acceleration of 4.50 rad/`s^(2)`. What is the magnitude of the net force acting on the object after a time of `t=1/3` s if the object remains at rest with respect to the disk ?

Options

A. 0N
B. `1.5xx10^(-2)N`
C. `7.4xx10^(-3) N`
D. `1.8xx10^(-2) N`

Answer

B

Explanation

`a=sqrt((Ralpha)^(2)+(omegaR)^(2))`
`=sqrt((0.3xx4.5)^(2)+(4.5xx1/3)^(2)xx0.3)^(2)`
`sqrt((135^(2))/(100^(2))(225/100xx3/10)^(2))`
`=1/100sqrt(135^(2)+(675^(2))/100)=150 m//s^(2)`
`F=ma=1.5xx10^(-2) N`