1. The problem statement, all variables and given/known data Dan is gliding on his skateboard at 3.00m/s . He suddenly jumps backward off the skateboard, kicking the skateboard forward at 6.00m/s (as measured by an observer on the ground). Dan's mass is 40.0kg and the skateboard's mass is 5.00kg . How fast is Dan going as his feet hit the ground? 2. Relevant equations vf-vi=vexplosion*ln(mf/mi) 3. The attempt at a solution vi=3 m/s mi=45 kg mf of dan=40 kg I used 6 m/s as vex when I plugged the above in the equation to find vf I got 2.29 which was marked wrong. Is it wrong to use 6m/s for Vex?