Question

a coolie with a heavy load of mass 5kg on his head is moving on a plane road for 20 minutes.calculate the work done by the coolie​

Answer 1

Answer:

ANSWER AS FOLLWS

Explanation:

THE WORK DONE IS ZERO. THE FORMULA OF WORK DONE IS (WD=F.S OR F.SCOS(theta) . HERE THE THETA IS 90° so, cos(90)° is 0 so,the correct answer is w.d =o

Answer 2

Answer:

work done is written as W = F.s = FsCosθ here F is the force applied, s is the displacement caused such that  

F = mg = 10 X 10 = 100 N s  

W( horizontal direction)= FsCos(0)=500J ,  θ is the angle between (vectors) F and s now,

as F and s are perpendicular for vertical direction, θ = 90 thus, W = FsCos90 = 0

And if you don't know trigonometry and vectors, then keep in mind that when force and displacement are perpendicular, the work done is always zero.