Question

The block of mass $m$ equal to $100kg$ is being pulled by a horizontal force$F$ $=$ $2mg$ applied to a string as shown in figure $(Takeg=10m/s^2).$ The pulley is massless and is fixed at the edge of an immovable table. What is the value of force exerted by the supporting cable (rod) on the pulley (in newton).

• A. $2mg$
• B. $\sqrt{2}mg$
• C. $2\sqrt{2}mg$
• D. $3\sqrt{2}mg$

Answer 1

Answer: (C)

$2\sqrt{2}mg$

Tension in string is $T^{\prime }=T=F=2mg$

From FBD,

$N=(T+T^{\prime })\cos \left({45}^o\right)$

$N=4mg\cos \left({45}^o\right)$

$N=2\sqrt{2}mg$