Dan is gliding on his skateboard at 2.00 m/s . He suddenly jumps backward off the skateboard, kicking the skateboard forward at 6.00 m/s. Dan's mass is 40.0 kg and the skateboard's mass is 7.00 kg. How fast is Dan going as his feet hit the ground?

Agroup of students were investigating the force of gravity. they began by dropping a foam ball from a height of 3 meters into a bucket of sand. the ball hit the sand in 0.306 seconds. they dropped additional balls of approximately the same diameter, but of different masses. here is the data they collected. based on this experiment and the collected data, what would their conclusion be?