Question

10th Grade Physical Science
Cassy shoots a large marble (Marble A, mass: 0.06 kg) at a smaller marble (Marble B, mass: 0.03 kg) that is sitting still. Marble A was initially moving at a velocity of 0.7 m/s, but after the collision it has a velocity of –0.2 m/s. What is the resulting velocity of marble B after the collision? Be sure to show your work for solving this problem along with the final answer.

Answer 1

Momentum is conserved.
\[mv _{A _{i}}+ mv _{Bi} = mv _{B _{f}}+mv _{Bf}\].
Rearranging this formula:
\[(m _{A} v _{A _{i}} + m _{B} v _{Bi} - m _{A}v _{A _{f}})/m _{B} = v _{Bf}\].
Now the \[m _{Bi}v _{Bi}= 0\] because the v=0 so
inserting the values
(0.06x0.7 - .06x-0.2)/ 0.03 =1.8 m/s in the direction that A was initially travelling.
Just check my calculation to be sure.