You've taken a summer job at a water park. In one stunt, a water skier is going to glide up the 2.0-m-high frictionless ramp shown, then sail over a 5.0-m-wide tank filled with hungry sharks. You will be driving the boat that pulls her to the ramp. She'll drop the tow rope at the base of the ramp just as you veer away.
What minimum speed must you have as you reach the ramp in order for her to live to do this again tomorrow?
U=mgh, K=0.5mv^2, W=Fd
The Attempt at a Solution
when the water skier is standing on the ramp, there is only gravitational potential energy
then, when I am pull the water skier, there are kinetic energy and work by pulling the water skier
Ef=K+W=0.5mv^2+5F, F=mg because the skier is skiing on water
thus, Ei+Ef= m*g*2=0.5mv^2+5mg= g(h-d)=0.5v^2
I get v=7.7m/s
I am not sure this is the right answer or not.