A block of mass m is stationary with respect to a wedge of mass M moving with uniform speed v on a horizontal surface. Find the work done by friction force on the block in t second.

Question

A block of mass m is stationary with respect to a wedge of mass M moving with uniform speed v on a horizontal surface. Find the work done by friction force on the block in t second. <img class="img-fluid question-image" alt="Question" src="https://cdn.tardigrade.in/q/nta/p-uothfhxfqavu.png" /> (A) zero (B) -(m g v t/2)sin 2θ  (C) -(m g v t/2) (D) -(m g v t/2)sin2 θ

Tardigrade Admin · Accepted Answer

<img class="img-fluid question-image" alt="Solution" src="https://cdn.tardigrade.in/q/nta/p-uothfhxfzzka.png" /> As the block is at rest with respect to wedge, fr=mgsin θ Work done by friction W=FScos θ W=-(m g sin θ )(v t)cosâ¡θ W=-(m g sin 2 θ /2)(v t)

Q. A block of mass $m$ is stationary with respect to a wedge of mass $M$ moving with uniform speed $v$ on a horizontal surface. Find the work done by friction force on the block in $t$ second.

zero

$- \frac{m gv t}{2} s in 2 θ$

$- \frac{m gv t}{2}$

$- \frac{m gv t}{2} s i n^{2} θ$

As the block is at rest with respect to wedge,
$f_{r} = m g s in θ$
Work done by friction
$W = FS cos θ$
$W = - (m g s in θ) (v t) cos θ$
$W = - \frac{m g s in 2 θ}{2} (v t)$

Q. A block of mass m is stationary with respect to a wedge of mass M moving with uniform speed v on a horizontal surface. Find the work done by friction force on the block in t second.