Speed is a scalar quantity that refers to “how fast an object is moving.”
The correct answer would be [ a spring scale. ]
I hope this helps!!!
Using the conservation of momentumwhere momentum = mass x velocity
so the let x be the initial velocity of the ball B
(30 kg) (-10 m/s) + (10 kg) (x) = (30 kg) (30 m/s) + ( 10 kg) (-10 m/s)
-300 + 10 x = 900 - 10010x = 900 - 100 + 30010x = 1100x = 1100 / 10x = 110 m/s