Teaching JKPSC Lecturership Mock Test Series 2024-25 Physical Sciences Classical Mechanics Rigid Body Dynamics
A block of mass m slides along the x axis with velocity \( \mathbf{v} = v \hat{i} \) . If the block encounters a friction force \(\mathbf{f} = -f \hat{i} \) , what is the time rate of change of angular momentum ( \( d\mathbf{L}_B/dt \) ) about point B ?
1
\( \frac{d\mathbf{L}_B}{dt} = 0\)
2
\(\frac{d\mathbf{L}_B}{dt} = -f l \hat{k}\)
3
\(\frac{d\mathbf{L}_B}{dt} = -l v \hat{k}\)
4
\(\frac{d\mathbf{L}_B}{dt} = f l \hat{i} \)