Question

Two billiard balls of the same mass are moving towards each other. Mass 1 (m1) is moving to the right at 6.0 m/s while mass 2 (m2) is moving to the left at 4.0 m/s. If the collision is an elastic head-on collision, what will be the velocity of m2 after the collision?6.0 m/s to the left4.0 m/s to the left6.0 m/s to the right4.0 m/s to the right

Answer 1

we have 2 balls with the same mass

just by the concept of elastic collision the speed will be exchanged

so m2 will have 6 m/s to the right

if we go by the equation

$m_1u_1+m_1u_2=m_1v_1+m_1v_2$

by conservation of momentum

Given here is

m1=m2

u1=6 m/s

u2= -4 m/s (negative sign for the direction)

v1=?

v2=?

Putting these values in the equation above

$\begin{gathered} u_1+u_2=v_1+v_2 \\ 6-4=-4+6 \end{gathered}$

Result: Option C is correct