Question

A porter moving vertically up the stairs with a suitcase on his head does work.Why.

Answer 1

Answer:

In case of physics, he doesn't do any work. Because, work done=mgCos theta. He moves vertically. So the angle is 90°.

W=mg cos90°=0.therefore he doesn't do any work.Due to this, if a porter moving vertically up the stairs with a suitcase on his head he feels weightlessness.

Answer 2

if we think as a physicist,then we will say he is not doing work,bcozwork is mgcos(a)

and the the value of cos 90 is always zero so the work will be zero.

however, biological,the Porter's muscles does the work in that activity,that why he feel tired after carrying the suitcase.

hope it helps you dude