4)
The tension force acts upwards and it equals the downward force of the box which is equal to its weight. The formula for calculating the weight of the box is expressed as
Weight = mass x acceleration due to gravity
acceleration due to gravity = 9.8 m/s^2
mass of box = 4.2
Weight = 4.2 x 9.8 = 41.16N
Tension = weight = 41.16 N
The tension in each rope is 41.16N