Question

Two balls have masses 18 kg and 47 kg. The 18 kg ball has an initial velocity of 76 m/s (to the right) along a line joining the two balls and the 47 kg ball is at rest. They make a head-on elastic collision with each other. What is the final velocity of the 18 kg ball?

Answer 1

The final velocity of 18 kg ball is
`V_(2)` = 42.09
`(m)/(sec)`

Step-by-step explanation:

Mass of first ball
`m_(1)` = 18 kg

Mass of second ball
`m_(2)` = 47 kg

Initial velocity of 18 kg ball
`V_(1)` = 76
`(m)/(sec)`

Initial velocity of 47 kg ball = 0

Final velocity of 18 kg ball
`V_(2)` = ??

Final velocity of 18 kg ball is given by the formula

`V_(2)` =
`(2 m_(1) V_(1) )/(m_(1) + m_(2) )`

Put all the values in above formula we get

`V_(2)` = 2 × 18 ×
`(76)/(65)`

`V_(2)` = 42.09
`(m)/(sec)`

Thus, the final velocity of 18 kg ball is
`V_(2)` = 42.09
`(m)/(sec)`