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: Physics Questions

  1. Oct 16, 2007 #1
    Physics Questions!!

    1. The problem statement, all variables and given/known data
    Gloria is pulling her baby in his sled. The baby and sled have a mass of 75 kg. If she is holding the rope to the sled at a 45o angle and she wants to accelerate at 0.5 m/s2 how much force does she need to exert?

    2. Relevant equations
    d = v x t vavg = ½ (vf + vi) vf = at + vi
    a = (vf - vi) / t d = vi t+ ½ at 2 vf2 = vi2 + 2ad
    d = (vf2 - vi2)/2a F = ma g = acceleration due to gravity = -10 m/s2; Pressure = N/m2 = Pa

    3. The attempt at a solution
  2. jcsd
  3. Oct 16, 2007 #2


    User Avatar

    Staff: Mentor

    You must show us your attempt at a solution before we can help you. That's one of the PF rules (see the "Rules" link at the top of the page).

    So how would you start this problem?
  4. Oct 16, 2007 #3
    Well my attempt would be as followed:

    Since I know the mass of 75kg and the acceleration (.5m/s2) I now know Fnet in the equation Fnet = Ftension + Fg. Now how do I incorporate an angle into this problem?
  5. Oct 16, 2007 #4
    Resolve the force so everything is along the same line.
  6. Oct 16, 2007 #5
    Yes but how would I go about solving the problem?
  7. Oct 16, 2007 #6
    And then you have one force that is multiplied by some trig function, equal to some other forces. You have enough information to solve this problem. Show us some of your working out.
  8. Oct 16, 2007 #7
    I have force due to gravity which is mg (75kg)(-10m/s^2). Do I solve for that and then use trig. I do not know?
  9. Oct 16, 2007 #8


    User Avatar
    Gold Member

    No, you need to work out the component of the force due to gravity that is acting on the sled. As was already said, resolve the components to one line.

    Draw a diagram of exactly what is happening and what you think the forces acting upon it are, and if possible show us this diagram.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook