A 2kg trolley moves to the right (positive x-direction) toward a 3kg trolley at rest on a frictionless horizontal track. After a perfectly elastic head-on collision, the 2kg trolley is observed to move to the left at 2ms−1, while the 3kg trolley moves to the right at 8ms−1. Determine the initial speed of the 2kg trolley.
a) 8ms−1
b) 12ms−1
c) 10ms−1
d) 6ms−1