Question

What is the maximum value of the force F such that the block shown in the arrangement, does not move ($\mu = 1/2\sqrt{3}$)

• A. 20 N
• B. 10 N
• C. 12 N
• D. 15 N

Answer 1

Answer: (A)

20 N

Answer 2

Frictional force $f = \mu R$

⇒ $F\cos 60 = \mu(W + F\sin 60)$

⇒ $F\cos 60 = \frac{1}{2\sqrt{3}}\left( \sqrt{3}g + F\sin 60 \right)$

⇒ $F = 20N$.