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

Answer:

The final velocity of 18 kg ball is $V_{2}$ = 42.09 $\frac{m}{sec}$

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 $\frac{m}{sec}$

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

$V_{2}$ = $\frac{2 m_{1} V_{1} }{m_{1} + m_{2} }$

Put all the values in above formula we get

$V_{2}$ = 2 × 18 × $\frac{76}{65}$

$V_{2}$ = 42.09 $\frac{m}{sec}$

Thus, the final velocity of 18 kg ball is $V_{2}$ = 42.09 $\frac{m}{sec}$