A4.0-kilogram ball moving at 8.0 m/s to the right collides with a 1.0-kilogram ball at rest. after the collision, the 4.0-kilogram ball moves at 4.8 m/s to the right. what is the velocity of the 1-kilogram ball?

Use conservation of momentum.  Check to see if your answer makes sense.  A heavy ball moving right hits a stationary ball.  Afterwards they should both be moving right and the lighter ball should be moving faster.

Definitely the indoraptor

Hi.the measurement  amperes represents the rate at which current flows.it's like the measurement of water flowing through a pipe.~