Force over a frictionless Surface

In summary, the problem is about a person pushing a crate over a frictionless surface with a constant force. The question is if the person would eventually need to start running with the crate or if there are other methods to keep applying a constant force. Several suggestions are given, such as using a long stick, attaching a string and spring, or tilting the surface. However, it is important to focus on what really matters in physics and to consider conservation of momentum in the analysis of the problem.
  • #1
nDever
76
1
Hey,

A certain problem in my physics textbook states that a person pushes a crate over a frictionless surface with a constant force.

If the crate accelerates, wouldn't the person eventually have to start running with it in order to keep applying force to it?
 
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  • #2
Yes. But he wouldn't be able to, because he'd fall on the ice first.:wink: Perhaps he could push it with constant force from a chopper. Or just let go of the crate and let it move at some constant speed (neglecting resisting forces like air).
 
  • #3
Deleting a trivial response
 
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  • #4
nDever said:
Hey,

A certain problem in my physics textbook states that a person pushes a crate over a frictionless surface with a constant force.

If the crate accelerates, wouldn't the person eventually have to start running with it in order to keep applying force to it?

Physics is difficult enough as it is without worrying about things that really do not matter in trying to understand and tackle this problem. I suggest you concentrate on what really matters.

Zz.
 
  • #5
I like your query and will re-post my original response... he could push with a long stick. I have tried to think of other ways and I am still thinking about it (have lots of time)
To raise the level I would add that conservation of momentum could be used to analyse the resulting motion and I believe that the centre of mass of the system would remain fixed.
However, I do not know what really matters in physics.
 
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  • #6
@#2, #5: The OP's question doesn't say the person is also standing on the frictionless surface. Think about pushing a crate along a roller track, for example.

Also, what ZZ said.
 
  • #7
If he is standing on the frictionless surface this becomes a very interesting physics problem !
 
  • #8
You could attach a string to the far end of the crate, pass it over a frictionless, massless pulley, pull the string back with an attached spring ensuring that the spring extension is constant.
It is a common mistake to assume that you could attach a mass to the string and expect its weight to provide a constant force. Don't get caught by that nDever !
 
  • #9
you could tilt the frictionless surface to 30 degrees then the object would experience a constant force of 0.5W (W = weight of crate) down the slope WITHOUT the person touching the crate...ZZZZZZZ
 
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Related to Force over a frictionless Surface

1. What is force over a frictionless surface?

Force over a frictionless surface refers to the amount of physical energy applied to an object that is moving across a surface with no friction. This means that there is no resistance or opposition to the motion of the object due to the absence of friction.

2. How is force over a frictionless surface different from force over a surface with friction?

The main difference is that when a force is applied to an object over a frictionless surface, there is no resistance to its motion. However, when a force is applied to an object over a surface with friction, there is an opposing force that acts in the opposite direction of the motion, which can slow down or stop the object.

3. What are some real-life examples of force over a frictionless surface?

An example of force over a frictionless surface is a hockey puck sliding across an ice rink. The lack of friction between the puck and the ice allows it to slide smoothly and quickly across the surface. Another example is a marble rolling on a smooth table, where there is minimal friction to slow down its motion.

4. How does the absence of friction affect the amount of force required to move an object over a surface?

The absence of friction means that there is no opposing force to overcome, so less force is needed to move an object over a surface. This is why it takes less effort to push a book across a smooth, frictionless table compared to a rough, carpeted surface.

5. What are the implications of force over a frictionless surface in scientific experiments?

Force over a frictionless surface is often used in scientific experiments to eliminate the effects of friction and isolate the forces acting on an object. This allows for more accurate measurements and observations of the object's motion and the forces acting on it.

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