What is the maximum value of the force F such that the block shown in the arrangement, does not move?

Options

A. ` 5 N`
B. `10 N`
C. `15 N`
D. `20 N`

Answer

D

Explanation

`uarr : N = sqrt(3) g + F sin 60^(@) = sqrt(3) g + (sqrt(3) F)/(2)`
`f_(max) = mu N = (1)/(2 sqrt(3)) ( sqrt(3) g + (sqrt(3) F)/(2))`
`= 5 + (F)/(4)`
The block will not move if `F cos 60^(@) le f_(max)`
`(F)/(2) le 5 + (F)/(4) rArr F le 20`
`F_(max) = 20 N`