Force required to push an object a certain distance

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Discussion Overview

The discussion revolves around calculating the force required to push a static object a certain distance, taking into account static and kinetic friction. Participants explore the relationship between applied force, friction, and the motion of the object over a specified distance of 2 meters.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant notes that to start moving the object, a force slightly over 10N is needed to overcome static friction, and once moving, a force of 5N is sufficient to maintain constant speed against kinetic friction.
  • Another participant argues that the force required does not depend on the distance the object is pushed.
  • A different perspective suggests that once the force is removed, friction will decelerate the object, and kinematic equations can be used to determine the distance traveled based on deceleration and initial speed.
  • One participant introduces the concept of kinetic energy, stating that to slide the object 2 meters, a certain amount of kinetic energy must be imparted, which is influenced by the kinetic friction acting on the object.
  • It is proposed that there is no single answer for the force required, as varying approaches could involve applying different forces initially and adjusting as the object moves.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between force, distance, and the effects of friction. There is no consensus on a single method or answer for calculating the required force.

Contextual Notes

Participants mention various assumptions regarding the initial conditions, such as the need to overcome static friction and the effects of kinetic friction, but these assumptions are not universally agreed upon.

johnnnnyyy
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If someone wanted going to push a static object a certain amount of distance how would you calculate the force the person needs to apply to the object?
I know you have to take the static force of friction into account so let's say the force of static friction is 10N to get the object moving, I know you would have to take the Fnet to find the total force the object is given, Fa-10N. And then let's say the object has kinetic force of friction of 5N, how would you determine the force the man needs to push the object with to move the object 2 meters? And let's say the object ways 5kg. I just have no clue how I would be able to find the force. Does anybody have any equations that might help me or can explain this to me? I feel like I am missing something.
 
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Once the object starts moving, it will continue moving at a constant speed (that is, zero acceleration) if the net force on it is zero - and that happens when you apply 5N to overcome the opposing dynamic friction.

So in your example:
- An initial force of slightly over 10N is required to overcome the static friction and start the object moving.
- Once it's moving, 5N will keep it moving.
 
Looks like you are under false impression that the force will depend on the distance - it won't.
 
As I suggested in your previous thread,If you make it move with a force F,it will continue to move until the force is removed.Once you remove the force,Friction will decelerate it(F=ma)and make it stop.You can find the distance traveled using kinemetics equations,once you know the deceleration and its initial speed(at the time the force was removed)
 
johnnnnyyy - Are you talking about giving a box a short shove to get it moving? In which case it will reach some initial speed and you will have given it some Kinetic Energy. It will then slow down and stop as kinetic friction converts that to heat.

You can work out how much KE you need to give it to make it slide 2m...If the kinetic force of friction of 5N then you need to give it 5 x 2 = 10 Joules of KE but the whole answer isn't quite that simple..

If the static friction is 10N then you need to apply at least that much force to get it moving. If you continue to apply that much force the box will accelerate because the kinetic friction is lower. Provided you push with more than 5N, at some point it will have acquired enough KE to slide the remaining distance on it's own and you can stop pushing. The remaining distance will be less than 2m so 10 Joules is no longer the energy needed to give it.

In short there is no one answer for the force required. You could reduce the force from 10 down to 5N once it's moving and push it the whole way with 5N... or give it a very short push with a much higher force, say 1000N (which it give it 10 Joules in quite a short distance compared to 2m) and let it slide the rest of the way.
 
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