Question

A Roller Derby Exhibition recently came to town. They packed the gym for twoconsecutive weekend nights at South's field house. On Saturday evening, the68-kg Anna Mosity was moving at 17 m/s when she collided with 76-kg SandraDay O'Klobber who was moving forward at 12 m/s and directly in Anna's path.Anna jumped onto Sandra's back and the two continued moving together atthe same speed. Determine their speed immediately after the collision.

Answer 1

14.4 m/s

Step-by-step explanation:

mass of Anna (Ma) = 68 kg

speed of Anna (Va) = 17 m/s

mass of SandraDay (Ms) = 76 kg

speed of SandraDay (Vs) = 12 m/s

We can find their speed (V) immediately after collision from the conservation of momentum where

(Ma x Va) + (Ms + Vs) = (Ma + Ms) x V

where V = speed immediately after collision

(68 x 17) + (76 + 12) = (68 + 76) x V

2068 = 144 V

V = 2068 / 144 = 14.4 m/s