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: 6 Easy Questions

  1. May 25, 2008 #1
    1. The problem statement, all variables and given/known data
    1.)is it possible to move in a curved path in the absence of a force? Defend your answer.
    2.)What is the net force on a 1-N apple when you hold it at rest above your head? What is the net force when you release it?
    3.)What is the net force acting on a 1-kg ball in free fall?
    4.)When you kick a football, what action and reaction forces are involved, which force, if any, is greater?
    5.)Does a baseball bat slow down when it hits a ball? Defend your answer.
    6.) Two people of equal mass attempt a tug of war with a 12-m rope while standing on frictionless ice. When they pull of the rope, each of them slides toward the other. How do their accelerations compare, and how far does each person slide before they meet?

    2. Relevant equations

    3. The attempt at a solution

    1.) I have no idea, I would think that the item would just follow the path, and if the path was curved it would curve too.
    2.) 0, and then -10m/s because thats the rate at which it falls due to gravity.
    4.)The foot kicking the ball, and the ball kicking the foot, and the foot kicking the ball would be greater.
    5.) I don't know :(
    6.)I don't know. :(

    I have a test tommorow, and need answers before then, Thanks!!!
  2. jcsd
  3. May 25, 2008 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Here are some hints.

    1. Review Newton's 1st Law of Motion
    2. Okay, but watch the units. They are asking for acceleration. Your answer is a velocity.
    3. Again watch those units. They are asking for a force, not a velocity or acceleration. You may need to review Newton's 2nd Law of Motion.
    4, 5, and 6. Review Newton's 3rd Law of Motion.
  4. May 25, 2008 #3


    User Avatar
    Homework Helper

    10m/s is acceleration due to gravity, the force would just be its weight
    Free fall implies that an object has reached terminal velocity. Now answer,what is terminal velocity?

    From what law did you get these ("The foot kicking the ball, and the ball kicking the foot") forces from?
    why would you think and the foot kicking the ball would be greater this?
  5. May 25, 2008 #4


    User Avatar
    Science Advisor
    Homework Helper

    Hi vandorin! :smile:

    I'll just add this to Redbelly98's good hints:
    I think you're misunderstanding "path". The question means "curved path" in the abstract sense … in other words, simply a curve. :smile:
    I don't think so, and nor does wikipedia. "Free fall" basically means falling, with no strings attached etc! :smile:
  6. May 25, 2008 #5


    User Avatar
    Homework Helper

    :confused: I always thought that at terminal velocity you are in free fall.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook