Question

A block of mass $1kg$ is pulled along the curve path $ACB$ by a tangential force as shown in figure. The work done by the frictional force when the block moves from $A$ to $B$ is

• A. $5J$
• B. $10J$
• C. $20J$
• D. $-20J$

Answer 1

The correct option is C $20J$

Work done by friction

$=\int \overrightarrow{F}.\overrightarrow{ds}=\stackrel{x}{\underset{0}{\int }}\mu mg\cos \theta \frac{dx}{\cos \theta }$

$=\mu mgx=20J$