A body is in limiting equilibrium (i.e. just at the point of moving down) on a rough inclined plane of inclination 45°. What is its acceleration , if the angle of inclination is increased to 60° ?

Options

A. 2.5 m/s
B. `3.66 m//s^2`
C. `4.5m//s^2`
D. `5.5m//s^2`

Answer

B

Explanation

In this case, `45^(@)` is the angle of repose because the body is just on the point of sliding down and `theta=60^(@)` and `mu=tan45^(@)=1`
The acceleration of the body down the rough inclined plane is given by
`a=g[sintheta-mucostheta]`
`:." "a=10[sin60^(@)-1xxcos60^(@)]`
`=10[(sqrt3)/(2)-1/2]=(10)/2[sqrt3-1]=5[1.732-1]`
`:." "a=3.66m//s^2`