Question

A block of mass $m$ is pulled in the direction shown in the figure on a rough horizontal ground with a constant acceleration of magnitude $a$. The magnitude of the frictional force is:

• A. $Tcos\theta -ma$
• B. ${\mu }_{k}mg$
• C. ${\mu }_k(T-mg)$
• D. ${\mu }_{k}Tsin\theta$

Answer 1

The correct option is A $Tcos\theta -ma$

Let $f$ be the frictional force. From FBD the equation of motion of the block ,
$ma=T\cos \theta -f\Rightarrow f=T\cos \theta -ma$
Ans:(A)