Question

A body of mass 10 kg is lying on a rough plane inclined at an angle of ${30}^0$ to the horizontal and the co-efficient of friction is 0.5. The minimum force required to pull the body up the plane is ( g = 9.8 $m/s^2$).

• A. 914 N
• B. 91.4 N
• C. 9.14 N
• D. 0.914 N

Answer 1

The correct option is B 91.4 N

Firstly check how much friction is

$f=\mu N=0.5\times 10\times 9.8\times \frac{\sqrt{3}}{2}=4.9\sqrt{3}\times 5$

$=24.5\sqrt{3}$

so require force is

$F=\mu N+10gSin30$

$=24.5\sqrt{3}+5\times 9.8$

$F=91.4N$

Hence correct option is (B)