Problem solving with solution..help..help

Question

an 800N repairman is trying to find a leak in a frictionless roof with a slope angle of 30deg. he is secured by a rope passing over the top and down the vertical side of the house. the other end of the rope is held by his helper on the ground. what should be the wejght of the helper to hold the man in the roof?

Answer 1

You can just use the triangle approach.

- You draw a 90 deg triangle with one of the other 2 angles is 30 deg.

- The longest side of the triangle will be in vertical position.

- The line that is parralell to the roof is not the line make the 30 deg of the triangle.

After you're able to draw from my description(hope it's okay :D) then the longest side of the triangle is the weight of the repairman, 800N. Then just use Sin of 30 deg to find the side of the triangle that is parrallel to the roof, which also will be the weight of the helper.

So 800(N)xsin(30)=400N.

Just a conversion here: 1 Newton = 0.224 808 lb

So he is weight 400x0.224 808=89.92 lbs Pretty thin, i say!

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