1. Not finding help here? Sign up for a free 30min 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!

Net work problem with F cos theta

  1. Oct 29, 2010 #1
    1. The problem statement, all variables and given/known data
    The graph below shows the component (Fcos(theta)) of the net force that acts on a 5.0 kg block as it moves along a flat horizontal surface. Find (a) the net work done on the block and (b) the final speed of the block if it starts from rest at s = 0.

    The graph shows Fcos(theta)(N) as the y-axis and s (meters) as the x-axis. The coordinates are (0,0), (1,0), (1,2), (4,2), (4,-2), (6,-2), (6,0), (8,0), connected by straight lines in that order.


    2. Relevant equations

    Work=Force*Distance*cos(theta)

    3. The attempt at a solution

    I don't understand what the y value represents or what values to assign for theta. Please help!
     
  2. jcsd
  3. Oct 29, 2010 #2
    Work = Force x cos[tex]\Theta[/tex] x distance
    This is the area under the given graph between Fcos[tex]\Theta[/tex] and s
     
  4. Oct 29, 2010 #3
    Fcos[tex]\Theta[/tex] is the force acting in the direction of the motion of the body.
    The acceleration of the body in the direction of motion can be calculated as
    Force = mass x acceleration
    After finding acceleration use
    vf2 = vi2 + 2ax
     
    Last edited: Oct 29, 2010
  5. Oct 29, 2010 #4
    A=.25/5.0=.05 m/s

    Vf=sqrt(2*.05*8)=.8944 m/s^2

    Thank you for your help!!!
     
  6. Oct 30, 2010 #5
    Thank you for giving new problem to me.:smile:
    Is the answer correct?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Similar Discussions: Net work problem with F cos theta
  1. Force/net work problem (Replies: 2)

Loading...