Question

A man weighing 50 kgf carries a load of 10 kgf to the top of a building in 4 minutes. The work done by him is 6*10^4 J. If he carries the same load in 8 minutes, what will be the work he’s done?

Answer 1

Answer:

6 x 10^4 J

Explanation:

Work done = mgh -----------     (1)

m = 50kg + 10kg = 60kg

g = 10 m/s^2

h = ?

Substituting values, we get

6 x 10^4  = 60 x 10 x h

6 x 10,000 = 6 x 10 x 10 h

By canceling 6 and 100, we get

h = 100 m

Justification:

From the above    6 x 10^4  = 60 x 10 x h

Substitute value of h, we get

6 x 10,000 = 6 x 10 x 10 x 100

60,000 = 60,000

6 x 10^4 J = 6 x 10^4 J

LHS = RHS

Assumption:

Let us assume that height was given instead of work done (h = 100m)

then,        Work done = mgh

                                   = 60 x 10 x 100 J

                                   = 60,000 J

                                   =6 x 10^4 J

Hope you got it !!!