I need help with the homework assignment. It's about momentum conservation in explosions and collisions. I tried the first page and I believe I got the initial and final calculations wrong. What formula should I use to solve parts 1 and 2 and the analysis.

Purpose: To analyze the change in momentum of a two-objects-system, when they interact. Equipment: red cart, blue cart, frictionless horizontal track, meterstick and timer PART 1-"The Explosion" Before After Run 1 (mred > Mblue) Hypothesis (predict how momentum of red cart compares to momentum of blue cart when they move) Magnet will be opposite direction. Data (COMPLETE DATA TABLES for Runl and Run2): not equal Explosive mred (kg) initial Vred final Vred mblue (kg) initial Vblue final Volue initial Psystem final Psystem (m/s) (m/s) (m/s) (m/s) small 2 0 -0.20 1 0 +0.40 2.0=0kg/s 2(-20)=-40 medium 2 0 -0.40 1 0 +0.80 Kg cmis large 2 0 -0.80 1 0 +1.60 okgamis initial Psystem Run 2 (mred