What Is Sam's Top Speed and Travel Distance on Jet Powered Skis?

[aligass2004]

Homework Statement

Sam, whose mass is 80 kg, takes off across level snow in his jet powered skis. The skis have a thrust of 189N and a coefficient of kinetic friction on snow of 0.1. Unfortunately, the skis run out of fuel after only 12s. a.) What is Sam's top speed? b.) How far has Sam traveled when he finally coasts to a stop?

Homework Equations

Fk = uk(n)
F=ma

The Attempt at a Solution

I solved part A by using F-uk(n) = m(Ax). I solved for Ax, and got the answer to be 1.3815. I then used acceleration = velocity/time to find the velocity. I got the velocity to be 16.578, which is right. For part B I tried using Vxf^2 = Vxi^2 + 2(Ax)(delta x) to find the change in displacement. I got 198.936m, which was wrong.

 

[Mentz114]

For the second part use the fact that
Frictional_force x distance = work_done_to_stop_skier = kinetic_energy_of_skier.

 

[m2003]

I would like to point out that the calculated top speed of 16.578 m/s is only an approximation as it assumes constant acceleration, which may not be the case in this scenario. Additionally, the coefficient of kinetic friction may vary depending on the conditions of the snow, which could affect the accuracy of the calculations. Furthermore, the use of jet powered skis on snow may have safety implications and it is important for individuals to use caution and follow proper safety protocols when engaging in such activities. As for part B, the equation used (Vxf^2 = Vxi^2 + 2(Ax)(delta x)) may not be applicable in this scenario as it assumes constant acceleration and does not take into account the decrease in velocity due to the skis running out of fuel. Further calculations or assumptions would be needed to accurately determine the distance traveled by Sam before coming to a stop.