A 4.45 g object moving to the right at 18.6 cm/s makes an elastic head-on collision with an 8.9 g object that is initially at rest. 18.6 cm/s
4.45 g
8.9 g
Find the velocity of the first object immediately after the collision. The acceleration of gravity is 9.8 m/s 2 . Answer in units of cm/s.

v₁f = -6.2 cm/s

Explanation:

Assuming no external forces acting during the collision, total momentum must be conserved, as follows:

       

As the collision is elastic, total kinetic energy must be conserved also:

       

From the givens, we know that m₂ = 2* m₁Replacing in the above equations, rearranging both sides and simplifying, we can find the following expression for v₁f:

       

v₁f = -6.2 cm/s (which means that it bounces back after the collision).