FrictionHardBloom L1
Question
The coefficient of friction between the block and plank is μ and ground is smooth. The value of µ is such that block becomes stationary with respect to plank before it reaches the other end. Then which of the following statement is incorrect.
Options
A.The work done by friction on the block is negative.
B.The work done by friction on the plank is positive .
C.The net work done by friction is negative.
D.Net work done by the friction is zero.
Solution
Sol.
mv0 = (M + m)v ⇒ v = $\frac{mv_{0}}{(M + m)}$
$(\Delta K)_{system} = \frac{1}{9}(M + m)u^{2} - \frac{1}{2}mu_{0}^{3} = \frac{1}{9}(M + m)\left\lbrack \frac{mv_{0}}{M + m} \right\rbrack^{2} - \frac{1}{2}mv_{0}^{2}$
$= \frac{1}{2}\left( \frac{m^{2}}{M + m} \right)u_{0}^{2} - \frac{1}{2}mv_{0}^{2} = \frac{1}{9}mv_{0}^{2}\left\lbrack \frac{m}{M + m} - 1 \right\rbrack$
∴ Total work of friction is
Create a free account to view solution
View Solution FreeMore Friction Questions
An insect of mass m, starts moving on a rough inclined surface from point A. As the surface is very sticky, the coeffici...The minimum velocity (in ms-1) with which a car driver must traverse a flat curve of radius 150 m and coefficient of fri...A block of mass 15 kg is resting on a rough inclined plane as shown in figure. The block is tied up by a horizontal stri...A block A of mass m1 rests on a horizontal table. A light string connected to it passes over a frictionless pulley at th...Which of the following is dimensionless :-...