A 43.9 kg student runs down the sidewalk and jumps with a horizontal speed of 4.03 m/s onto a stationary skateboard. The student and skateboard move down the sidewalk with a speed of 3.85 m/s.
a) find the mass of the skateboard. answer in units of kg
b) How fast would the student have to jump to have a final speed of 6.93 m/s. Answer in units of m/s.
I assume I would need to find how fast he runs down the sidewalk to begin? Would I then add that to the horizontal speed, or would I have to add them like vectors...?