Question

In the given diagram, with what force must the man pull the rope to hold the plank in position? $($Mass of the man is $80k$; neglect the weight of the plank, rope and pulley; take $g=10{m/s}^2)$

• A. $200N$
• B. $300N$
• C. $600N$
• D. $150N$

Answer 1

The correct option is A $200N$

If the rope exerts a tension $T$ on the man, the tensions in the othe ropes will be as shown in the figure.


Treating the man and planck as one system, FBD can be drawn as follows.


$4T=mg=800$
$T=200N$