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Homework Help: Force, Mass, and Acceleration Questions

  1. Mar 8, 2007 #1
    I have about five questions here that I'm clueless about and need help with.

    A. If mass increases and acceleration remains the same, force will _____?
    B. If acceleration decreases and mass remains the same, force will _____?
    C. If force increases and mass remains the same, acceleration will _____?
    D.If force decreases and acceleration remains the same, mass will _____?

    I'm not the best at science, and I've tried to give this thought, but I left my notes at school and can't get them until tomorrow (which is when this whole assignment is due.)

    I know the answers are in my notes, but I can't access them.

    I made an attempt guess at number 1, guessing that force will slow down.
  2. jcsd
  3. Mar 8, 2007 #2


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    Gold Member

    force = mass * acceleration is all you need for this.
  4. Mar 8, 2007 #3
    What does Newton's Second Law say, that the force is proportional to the mass and acceleration?
  5. Mar 8, 2007 #4
    If you don't know just do what the problem says:
    Say you start off with a force of 10N, and acceleration of 5m/s/s, and a mass of 2kg.
    The problem asks if the mass increases while acceleration is constant, what will happen to the force. So just keep the same acceleration (5m/s/s) and multiply it by a mass that is greater the 2kg, since your mass increased. Did the Net Force get bigger or smaller? You can do this for all of them if you need to.
  6. Mar 8, 2007 #5
    Thanks! That was useful, I think I've got three of the answers now. But not the last one...
  7. Mar 8, 2007 #6


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    Staff Emeritus
    Science Advisor

    Consider the equation f=ma. If you decrease the force, and the acceleration remains constant, what happens to the mass? Try putting some numbers in if you're not sure.
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