Ask Question
29 June, 06:45

The boom of a fire truck raises a fireman (and his equipment - total weight 280 lbf) 60 ft into the air to fight a building fire. (a) Showing all your work and using unity conversion ratios, calculate the work done by the boom on the fireman in units of Btu. (b) If the useful power supplied by the boom to lift the fireman is 3.50 hp, estimate how long it takes to lift the fireman.

+1
Answers (1)
  1. 29 June, 09:47
    0
    a) Work done by fireman = 2.15 Btu

    b) Time t = 0.86 sec

    Explanation:

    Given that

    Weight = 280 lbf

    We know that 1 lbf = 4.44 N

    so 280 lbf = 1245.5 N

    Weight = 1245.5 N

    Height h = 60 ft

    We know that

    1 ft = 0.3048 m

    So 60 ft = 18.28 m

    h = 18.28 m

    Power = 3.5 hp

    We know that

    1 hp = 0.74 KW

    So 3.5 hp = 2.61 KW

    Power = 2.61 KJ/s

    So the work done by fireman = Weight x h

    Now by putting the values

    Work done by fireman = 1245.5 x 18.28 J

    Work done by fireman = 2267.74 J

    Work done by fireman = 2.26774 KJ

    We know that 1 Btu = 1.05 KJ

    So 2.266 KJ = 2.15 Btu

    Work done by fireman = 2.15 Btu

    We know that, rate of work is called power.

    Power x time = work

    2.61 x t = 2.26

    So t = 0.86 sec
Know the Answer?
Not Sure About the Answer?
Find an answer to your question ✅ “The boom of a fire truck raises a fireman (and his equipment - total weight 280 lbf) 60 ft into the air to fight a building fire. (a) ...” in 📘 Physics if you're in doubt about the correctness of the answers or there's no answer, then try to use the smart search and find answers to the similar questions.
Search for Other Answers