Question

2 painters, whose weight are 600 N and 750 N, stand on a scaffold wighing 300 N. Which of the following choices could be the tensions in the 2 support ropes?

a. 800 N and 900 N

b. 800 N and 850 N

c. 750N and 800 N

d. 850 N for both

e. none

Answer 1

Weight of the first painter = W₁ = 600 N

Weight of the second painter = W₂ = 750 N

Weight of the scaffold = W₃ = 300 N

Total downward force on the scaffold = W

W = W₁ + W₂ + W₃

W = 600 + 750 + 300

W = 1650 N

For the two support ropes to support the scaffold the total tension in both ropes should be 1650 N.

Option (a) -> 800 + 900 = 1700 N

Option (b) -> 800 + 850 = 1650 N

Option (c) -> 750 + 800 = 1550 N

Option (d) -> 850 + 850 = 1700 N

Only option (b) satisfies that the total tension in both ropes is 1650 N.

Option (b) is only choice which could be the tensions in the 2 support ropes.