1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Work & forces help

  1. Jul 8, 2017 #1
    1. The problem statement, all variables and given/known data
    You are a member of an alpine rescue team and must project a box of supplies, with mass m, up an incline of constant slope angle α so that it reaches a stranded skier who is a vertical distance h above the bottom of the incline. The incline is slippery, but there is some friction present, with kinetic friction coefficient μk.

    Use the work-energy theorem to calculate the minimum speed v that you must give the box at the bottom of the incline so that it will reach the skier.
    Express your answer in terms of some or all of the variables m, g, h, μk, and α.

    2. Relevant equations
    Work=1/2(mv^2)-1/2(mv^2)--------- the negative velocity being the initial.

    3. The attempt at a solution
    I got the correct solution through checking online because of the system telling me I did my trig. wrong. I need clarification as too why the answer was what it is. In the answer They use cos of the angle for the friction force, but when I break up the components, the x component of gravity is sin, so I don't understand how they got cosine.
  2. jcsd
  3. Jul 8, 2017 #2
    Please show us the details of what you did, including free body diagram.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted