A body of mass 1 kg is shifted from A to D on inclined planes by applying a force slowly such that the block is always in contact with the plane surfaces. Neglecting the jerk experienced at points C and B, total work done by the force is:

Question

A body of mass 1 kg is shifted from A to D on inclined planes by applying a force slowly such that the block is always in contact with the plane surfaces. Neglecting the jerk experienced at points C and B, total work done by the force is: (A) 90 J (B) 56 J (C) 180 J (D) 0 J

Tardigrade Admin · Accepted Answer

Work done: =M g h1+M g h2+M g h3+μ1 M g l1+μ2 M g l2+μ 3 M g l3 =M g(h1+h2+h3)+M g(μ1 l1+μ2 l2+μ3 l3) =M g(8+0.2+0.4+0.4) =90 J

Q. A body of mass $1 k g$ is shifted from $A$ to $D$ on inclined planes by applying a force slowly such that the block is always in contact with the plane surfaces. Neglecting the jerk experienced at points $C$ and $B$ , total work done by the force is:

$90 J$

$56 J$

$180 J$

$0 J$

Work done:
$= M g h_{1} + M g h_{2} + M g h_{3} + μ_{1} M g l_{1} + μ_{2} M g l_{2} + μ 3 M g l_{3}$
$= M g (h_{1} + h_{2} + h_{3}) + M g (μ_{1} l_{1} + μ_{2} l_{2} + μ_{3} l_{3})$
$= M g (8 + 0.2 + 0.4 + 0.4)$
$= 90 J$

Q. A body of mass 1kg is shifted from A to D on inclined planes by applying a force slowly such that the block is always in contact with the plane surfaces. Neglecting the jerk experienced at points C and B, total work done by the force is:

90J

56J

180J

0J