Question

The man carrying a suitcase walks on a horizontal surface work done by him with respect of gravity is

A)positive
B)zero
C)negative
D)both positive and negative

Plz answer this

Answer 1

$\huge\mathfrak\red{Answer}$

WHAT DO YOU MEAN BY

WORK DONE?

IN PHYSICS WORK TERM IS VERY USED FOR THE DOT PRODUCT OF FORCE WITH DISPLACEMENT. BY DOT PRODUCT I MEAN TO CONCLUDE THAT THE PRODUCT OF MAGNITUDE OF FORCE WITH COMPOSITION OF DISPLACEMENT OVER THE FORCE.

$let \: f\: be \: the \: force \: applied \: at \: an \: \\ angle \: \alpha \: with \: the \: displacement(ds) \\ \\ than \: small \: work \:( dw )\: equals \: to \\ \\ dw = f.ds \cos \alpha \\ \\ according \: to \: your \: question \\ f = mg \\ let \: displacement = s \\ \alpha = 90 \\ \\ dw = f.ds \cos \alpha \\ dw = f.s \cos90 \\ dw = f.s(0) \\ dw = 0 \\ work \: done \: is \: zero$

Answer 2

Answer:

zero

Explanation:

work done =fcos90°×s

=f×0×s. (cos90°=0)

. =0

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