Question

The force required to just move a body up an inclined plane is double the force the required prevent it from sliding down. If phi is angle of friction and theta is the angle which incline makes with the horizontal then,
A. `tantheta=tanphi`
B. `tantheta=2tanphi`
C. `tantheta=3tanphi`
D. `tanphi=2tantheta`

Answer 1

Correct Answer - C
`mg(sintheta+mucostheta)=2mg(sintheta-mucostheta)`
`tantheta=3mu`
`tantheta=3tanphi` . `{ :. `mu=tanphi)` .