A) Magnitude of the force F:
The tension in the string between blocks B and C is the same as the net force acting on block B. The net force acting on block B is equal to the sum of the forces acting on it. These forces are the tension in the string between blocks A and B, the tension in the string between blocks B and C, and the gravitational force acting on block B. The magnitude of the net force acting on block B is given by the following equation:
F = TAB + T + m * g
where:
F = magnitude of the force
TAB = tension in the string between blocks A and B
T = tension in the string between blocks B and C
m = mass of each block
g = acceleration due to gravity (9.8 m/s^2)
Setting TAB + T = F, we have:
F = T + m * g
Rearranging the equation, we get:
T = (F - m * g)
So, the magnitude of the force F is given by:
F = T + m * g
B) Tension TAB in the string between blocks A and B:
Since the system is in equilibrium, the net force acting on block A must be equal to zero. The net force acting on block A is equal to the sum of the forces acting on it. These forces are the tension in the string between blocks A and B and the gravitational force acting on block A. The magnitude of the net force acting on block A is given by the following equation:
0 = TAB - m * g
Solving for TAB, we have:
TAB = m * g