Question

A particle of mass $M =02 \,kg$ is initially at rest in the $xy$-plane at a point $( x =-\ell, y =- h )$, where $\ell=10 \,m$ and $h =1\, m$ The particle is accelerated at time $t =0$ with a constant acceleration $a =10\, m / s ^{2}$ along the positive $x$-direction Its angular momentum and torque with respect to the origin, in SI units, are represented by $\vec{ L }$ and $\vec{\tau}$ respectively $\hat{ i }, \hat{ j }$ and $\hat{ k }$ are unit vectors along the positive $x , y$ and $z$-directions, respectively If $\hat{k}=\hat{i} \times \hat{j}$ then which of the following statement(s) is(are) correct?

• A. The particle arrives at the point $(x=\ell, y=-h)$ at time $t=2 s$.
• B. $\vec{\tau}=2 \hat{k}$ when the particle passes through the point $(x=\ell, y=-h)$
• C. $\vec{ L }=4 \hat{ k }$ when the particle passes through the point $( x =\ell, y =- h )$
• D. $\vec{\tau}=\hat{k}$ when the particle passes through the point $(x=0, y=-h)$

Answer 1

Answer: (C)

$\vec{ L }=4 \hat{ k }$ when the particle passes through the point $( x =\ell, y =- h )$

Answer 2

The correct answer is option (C): $\vec{ L }=4 \hat{ k }$ when the particle passes through the point $( x =\ell, y =- h )$