Consider a horizontal, uniform board of weight 125 N and length 4 m that is supported by vertical chains at each end. A person weighing 500 N is sitting on the board. The tension in the right chain is 250 N

What is the tension in the left chain?

a. 250 N

b. 375 N

c. 500 N

d. 625 N

e. 875 N

b. 375 N

Explanation:

System of forces in balance

ΣFy = 0 Equation (1)

Forces acting on the board

T₁: Tension in the left chain, vertical and upward

T₂ = 250 N : Tension in the right chain, vertical and upward

W₁ = 125 N : Weight of the board, vertical and downward

W₂ = 500 N : Weight of the person, vertical and downward

Calculation of the T₁

We apply the Equation (1)

ΣFy = 0

T₁+T₂-W₁-W₂ = 0

T₁ = - T₂+W₁+W₂

T₁ = - 250 N + 125 N + 500 N

T₁ = 375 N