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Can some one help me please?

  • 03-11-2010 10:13pm
    #1
    Ste234
    Registered Users, Registered Users 2 Posts: 65 ✭✭


    1. A horizontal force of 40 N acts for 3 s on a 20 kg body initially at rest. The coefficient of friction between the surfaces is 0.5. Find the acceleration and the final speed.


Comments

  • #2
    Morbert
    Registered Users, Registered Users 2 Posts: 3,457 ✭✭✭Morbert


    Ste234 wrote: »
    1. A horizontal force of 40 N acts for 3 s on a 20 kg body initially at rest. The coefficient of friction between the surfaces is 0.5. Find the acceleration and the final speed.

    If you know the coefficient of friction, and you know the weight of the bag, what will the force due to friction be?


  • #3
    ClutchIt
    Registered Users, Registered Users 2 Posts: 709 ✭✭✭ClutchIt


    Morbert wrote: »
    If you know the coefficient of friction, and you know the weight of the bag, what will the force due to friction be?

    20x9.81x0.5 = 98.1N


  • #4
    Morbert
    Registered Users, Registered Users 2 Posts: 3,457 ✭✭✭Morbert


    ClutchIt wrote: »
    20x9.81x0.5 = 98.1N

    Yes, but I was hoping Ste234 would answer it. As it would be a bad idea to simply post the answer.


  • #5
    ClutchIt
    Registered Users, Registered Users 2 Posts: 709 ✭✭✭ClutchIt


    True. I did show how I got it though and it's only 1 part of the problem. I knew why you didn't post the answer and you are totally right


  • #6
    FISMA
    Closed Accounts Posts: 2,616 ✭✭✭FISMA


    Step 1: draw a free body diagram
    Step 2: draw the Forces ON the body, not BY the body.
    Step 3: are you accelerating - yes or no?
    Step 4: sum up the Forces in the x direction and set equal to ma.
    Step 5: solve for a.


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