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!

Conveyor Belt's Power

  1. Jun 28, 2012 #1
    1. The problem statement, all variables and given/known data
    Sand falls at a rate of 0.5 kg/s onto a conveyor belt which is moving at a constant speed of 2.0 m/s.

    Questions:

    a. Find the power expended in driving the belt!
    b. Find the rate at which the sand acquires kinetic energy!
    c. Account for any difference between the answer in part (a) and (b)


    2. Relevant equations
    F = m.(dv/dt) + v (dm/dt)
    P = W/t = F.v


    3. The attempt at a solution
    For question (a), i think:
    P = F.v
    = [m.(dv/dt) + v (dm/dt)].v ; dv/dt = 0
    = (dm/dt) . v^2
    = ..... W

    Is it right ?

    For question (b) i have no idea about the question. The question asked about speed or Power ?

    Thanks a lot.
     
  2. jcsd
  3. Jun 28, 2012 #2
    you know that power = change in energy per second?
    Can you calculate the rate of change of KE per second of the sand?
     
  4. Jun 28, 2012 #3
    do you mean like this ?
    W = KE / t
    = 0.5 m v^2 / t

    m/t = 0.5 kg.
    v = 2 m/s

    so, W = 1 W ? is this right for question (b) ?

    and

    P = F.v
    = [m.(dv/dt) + v (dm/dt)].v ; dv/dt = 0
    = (dm/dt) . v^2
    = 2 W for question (a) ?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Conveyor Belt's Power
  1. Conveyor Belt Power (Replies: 1)

Loading...