Question

The force F needed to keep the block at
equilibrium in given figure is (pulley and string are
massless)
(1)Mg/5
(2)Mg/4
(3)Mg/2
(4)Mg/3​

Answer 1

Answer:

1) Let the tension in the string be 'T' .

Since, net force along the string is 0.

=> F-T=0

=> F=T

2) Now,

Tension is constant along the string .

=> Tension on both sides of pulley is 'T'.

We need, to find the value of 'F'  to keep the system in equilibrium .

=> Net force on pulley must be 0.

=> 2T-Mg = 0

=> T = mg/2.

Hence, the value of F=T=Mg/2.

Answer 2

Answer:

(3)mg/2

Explanation:

1) Let the tension in the string be 'T' .

Since, net force along the string is 0.

=> F-T=0

=> F=T

2) Now,

Tension is constant along the string .

=> Tension on both sides of pulley is 'T'.

We need, to find the value of 'F'  to keep the system in equilibrium .

=> Net force on pulley must be 0.

=> 2T-Mg = 0

=> T = mg/2.

Hence, the value of F=T=Mg/2.