Question

PLZ HELP 20 POINTS

PHYSICS CLASS 9

CORRECT SOLUTION WILL BE AWARDED BRAINLIEST


Thanks in advance

Answer 1

As-Salamu-Alykum


___________

(a )


Electron revolving in orbit has zero work because its final and initial points are same si displacement is zero

And we know that work is given by :-

W=Fd

if d=0

then....

W=F(0)

W =0


(b)

In case of stone dropped from the top of a building

Work = Potential energy

W= P.E

P.E =mgh

So

Work = mgh in this case


___________

INSHALLAH it will help U

Answer 2

$\huge\green{ASSALAMUALAIKUM!}$

=>(a) part...

workdone by an electron

revolving in a circular

orbit of radius "r" around

the neucleus is zero

because here force and displacement are at right angles (Φ=90°)

therefore, W=F.s cos90 = 0

=>(b) part....

when stone of mass "m" dropped from a top of

multi-storied building of height "h"

then,

workdone = potential energy

P.E.=mgh

hence,

workdone = mgh

$\huge\orange{INSHAALLAH it will help you!}$