A 200kg turtle running at a speed of .4m/s jumps onto a stationary skateboard that masses 3.6kg. the turtle slows to .2m/s by shooting the skateboard out from under him. how fast is the skateboard moving as a result?
After the turtle jumps on, conservation of momentum tells you that the velocity of both (V) is
200*0.4 = (200 +3.6)V
V = 0.393 m/s
To slow down the turtle to 0.2 m/s by shooting the skateboard forward, the skateboard achieves velocity v given by
203.6*0.393 = 200*0.2 + 3.6 v
3.6 v= 80.0 -40.0 = 40.0
v = 11.1 m/s