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A painter stands a horizontal platform which has a mass of 20kg and is 5m long, the platform is suspended by two vertical ropes , one attac
Question
A painter stands a horizontal platform which has a mass of 20kg and is 5m long, the platform is suspended by two vertical ropes , one attached to each end of the platform . the mass of the painter is 70kg . if he is standing 2m from the centre of the platform . Calculate the tension in each of the ropes.
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Physics
3 years
2021-08-22T13:58:05+00:00
2021-08-22T13:58:05+00:00 1 Answers
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Answers ( )
Answer:
R = 715.4 N
L = 166.6 N
Explanation:
ASSUME the painter is standing right of center
Let L be the left rope tension
Let R be the right rope tension
Sum moments about the left end to zero. Assume CCW moment is positive
R[5] – 20(9.8)[5/2] – 70(9.8)[5/2 + 2] = 0
R = 715.4 N
Sum moments about the right end to zero
20(9.8)[5/2] + 70(9.8)[5/2 – 2] – L[5] = 0
L = 166.6 N
We can verify by summing vertical forces
116.6 + 715.4 – (70 + 20)(9.8) ?=? 0
0 = 0 checks
If the assumption about which side of center the paint stood is incorrect, the only difference would be the values of L and R would be swapped.