How Fast and Far Can Jet Powered Skis Go?

  • Thread starter Thread starter aligass2004
  • Start date Start date
  • Tags Tags
    Displacement Speed
Click For Summary

Homework Help Overview

The discussion revolves around a physics problem involving jet powered skis, focusing on the dynamics of motion across snow. The scenario includes parameters such as thrust, friction, and mass, with the goal of determining the top speed and distance traveled before coming to a stop.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the initial conditions and the need to clarify what specific outcomes are being sought. There is an emphasis on using equations of motion and considering forces such as friction. Some participants share their attempts at calculating acceleration and velocity, while others express confusion about the second part of the problem.

Discussion Status

Guidance has been offered regarding the two-part nature of the problem, with suggestions to use relevant equations of motion and to visualize the scenario. Some participants have made progress in calculating initial conditions, but there remains uncertainty in addressing the subsequent motion after the power ceases.

Contextual Notes

Participants note the incomplete problem statement and the importance of understanding how friction affects the motion. There is also a mention of the need for clarity on the specific questions being asked in the problem.

aligass2004
Messages
236
Reaction score
0

Homework Statement



Sam, whose mass is 80kg, 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. Unfortuneately, the skis run out of fuel after only 12s.

Homework Equations


F=ma
kinematic equations

The Attempt at a Solution


I have no idea where to even begin with this problem.
 
Physics news on Phys.org
The problem statement is incomplete. What are you being asked to find?
 
I'm sorry. The question wants to know what Sam's top speed is, and how far has Sam traveled when he finally coasts to a stop.
 
OK, here are a couple of hints. This is a two part problem. The first part is the powered motion. Use your equations of motion to find the distance and velocity at the point where power quits and those are initial conditions for the 2nd part of the problem, which is coasting to a stop.

What are the relevant equations of motion? The need to involve mass, force, friction, etc. F=ma is a good start. Go a bit further. How does friction enter into the picture? If you haven't done it already, it REALLY helps to draw a picture and label the pertinent information.
 
Here's some help if you're having trouble visualizing it.

untitled4.jpg
 
Ok, I got part A by using F-uk(n) = m(Ax). I got the acceleration to be 1.3815. Using that I found the velocity, which is 16.578. I am having trouble figuring part B out. I tried using Vxf^2 = Vxi^2 + 2(Ax)(delta x).
 

Similar threads

Replies
1
Views
5K
Replies
9
Views
4K
Replies
6
Views
6K
Replies
7
Views
2K
  • · Replies 23 ·
Replies
23
Views
9K
  • · Replies 3 ·
Replies
3
Views
20K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
8K
  • · Replies 12 ·
Replies
12
Views
5K