Question

a body moving towards a finite body at rest collides with it.It is possible that
a.both the bodies come to rest
b.both the bodies move after collision
c.the statonary body remains stationary while the moving body changes its velocity

Answer 1

B! ^_^

Answer 2

why not c

Answer 3

Since the stationary body is finite, there has to be momentum transferred to it to satisfy conservation of momentum. Otherwise this happens:

\[p_i=p_f\]
\[ \text{is we assume the stationary body remains stationary;} \ v_{2i}=v_{2f}=0\]
\[m_1v_{1i} + m_2 \cancel{v_{2i}}^0=m_1v_{1f} + m_2\cancel{v_{2f}}^0\]
\[m_1v_{1i} =m_1v_{1f} \]
and the only way those terms are equivalent is if the moving body's momentum remains completely unchanged, which is impossible - the stationary body is in the path of the moving body, so would impart *some change in the direction or magnitude of the original velocity.

^_^