Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Newtons's 3rd Law

  1. Nov 30, 2006 #1
    1. The problem statement, all variables and given/known data
    In three different situations, clearly describe how you use Newton's 3rd law to your advantage.

    2. Relevant equations

    3. The attempt at a solution
    Because of Newton's 3rd law, I know that when I am playing tennis, the harder I hit the tennis ball, the faster it will go towards my opponent, making it easier to score. This is because the tennis ball will have equal magnitude as the action force I exert on it.
    (NOTE: My physics teacher read this and told me it was a bad example as it could be used for and example displaying Newton's 2nd law.)
  2. jcsd
  3. Nov 30, 2006 #2


    User Avatar

    Staff: Mentor

    Actually the relevant equations would be Newton's Laws. Could you please list them, and then think of another example of the 3rd Law?
  4. Nov 30, 2006 #3
    Well, This is like my first year of real physics, so Im guessing a related formula would be:
    And another example I can think of...umm, gimme a bit to think.
  5. Nov 30, 2006 #4
    Using a springboard to jump over an obstacle, knowing that the magnitude of my action force that I apply on the springboard will be equal to the magnitude of the reaction force it applies on me, I know the harder I push down on the springboard the higher it will launch me, thus takign advantage of Newtons third law.
    Hows that?
  6. Nov 30, 2006 #5
    An advantage i had would involve me standing on a trampoline..where when i jump and land i would be thrown back into the air at a height depending on the force that i had exerted coming down, so if i held a heavy weight which was heavy enough to allow me to jump...when I came down from a jump i would exert more force on the trampoline and I would go higher then before...

    I think that would be a valid answer but i may be wrong....
  7. Nov 30, 2006 #6
    In my opinion, to take advantage to that you would have to release the weight just as you are bouncing back up, because then you would have the magnitude of the weight and your body mass acting on just you and not the weight, giving you extra height. In my opinion.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook