A 95 kg fullback is running at 7.5 m/s to the east and is stopped by a head-on tackle by a tackler running due west a 12.4 m/s. What is the mass of the tackler?

Answer 1

Conservation of momentum
momentumEast-momentumWest=0
calculate the mass of the guy going west.

Answer 2

He/she may need a little bit more help if he/she needed to ask the question. MV+MV=0 so, (95Kg)(7.5m/s) + M(12.4m/s) =0, rearrange and solve. M=[(95Kg)(7.5m/s)]/(12.4m/s).