Recent content by AndrewMorris

oh man, I used to be good at maths, honest. Thanks :-)

Using conservation of momentum I would say (60 x 8) + (80 x 2) = (60 + 80) v so v = 400/140 = 2.86 m/s. However, this is not one of the multiple choice responses. What am I doing wrong?

Thanks for confirming!

To me, they all look incorrect. Oh hang on. Ultrasonic waves. I misread that. It's no 6 then.