Question

A block of mass m is placed at the point A on a rough track
shown in figure. If slightly pushed towards right, it stops at the
point B of the track. Calculate the work done by the frictional
force on the block during its transit from A to B.​

Answer 1

Explanation:

Given, m=1 kg,H=1 m,h=0.8 m

Here, work done by friction = change in P.E. [as the body comes to rest]

⇒Wf = mgh−mgH

=mg (h−H)

=1×10(0.8−1) = −2J

Answer 2

Explanation:

Given, m=1 kg,H=1 m,h=0.8 m

Given, m=1 kg,H=1 m,h=0.8 mHere, work done by friction = change in P.E. [as the body comes to rest]

Given, m=1 kg,H=1 m,h=0.8 mHere, work done by friction = change in P.E. [as the body comes to rest]⇒Wf = mgh−mgH

Given, m=1 kg,H=1 m,h=0.8 mHere, work done by friction = change in P.E. [as the body comes to rest]⇒Wf = mgh−mgH=mg (h−H)

Given, m=1 kg,H=1 m,h=0.8 mHere, work done by friction = change in P.E. [as the body comes to rest]⇒Wf = mgh−mgH=mg (h−H)=1×10(0.8−1) = −2J