Solving for distance using only initial velocity and coefficient of friction

In summary, the conversation discusses the difficulty of a physics problem involving a box sliding across a floor with an initial push. The question asks for the distance the box will go, given the coefficient of friction and initial speed. The conversation also includes attempts at a solution using equations such as force equals mass times acceleration and friction equals the coefficient of friction times the normal force. However, it is ultimately determined that conservation of energy and the equation for kinetic energy can be used to solve the problem. The conversation also mentions the possibility of the mass canceling out and provides a working formula for finding the initial velocity.
  • #1
manuela4
1
0
This problem is quite difficult for me. I know that there's a way to do this, but i can't figure it out. Could someone point me in the right direction? i don't need a solution, but a process would be nice.

Homework Statement


A box is given an initial push so that it slides across the floor. How far will it go, given that the coefficient of friction is 0.30 and the push imparts an initial speed of 3.0 m/s?

so Vi = 3.0 m/s, Vf= 0 m/s and Mu = .3
gravity is always active (at 9.81 m/s2), but i have no mass to calculate its force.

Homework Equations


all i know for friction:
F=ma (but i don't have mass, acceleration)
F= Mu Fn (Mu being the coefficient of friction, Fn being normal force)
i havnt chosen a distance equation because i don't have enough variables to do so.


The Attempt at a Solution


Without a formula, i can't solve... i can't even get started.
 
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  • #2
Use conservation of energy. You start with kinetic energy it goes into friction (ie heat).
Energy is force * distance, where the force is the frictional force slowing it down.
 
  • #3
You sure the question states only that? Cause I strongly think that there's not enough data to solve this problem.
 
  • #4
The mass cancels.
KE = 1/2 mv^2
Friction = distance*mgu
 
  • #5
mgb's prefectly right. apologies for not recognising that :)
 
  • #6
Actually, althought relating the Kinetic Energy equation to the equation about friction and distance might be conceptually valid, it isn't the clue this person needed.

At the early point (probably around chapter 4) of an "elementary physics" textbook, a student encounters problems where, given an initial velocity and coefficient of friction , the student is expected to provide the resulting final displacement. This is a stage of the textbook where kinetic energy equations and "work" equations have not yet been introduced, therefore there is a different solution.

Since this person made their inquiry in November of 2008, I'm sure they're not waiting for the answer anymore, but I will return with an answer tomorrow.
 
  • #7
I have the same problem, except that initial velocity is 2m/s
I know this is a bump, but it is the closest I can get to my question
 
  • #8
I have a similar question yet in reverse.

Given:
Final displacement = 12m
Coefficient of Friction = .28

Find:
Initial velocity = 0

I am assuming to look for an equation that cancels masses out, yet need help with the next step
 
  • #9
NVM I found a working formula.

1/2mv^2=displacement*mgu

so the masses cancel leaving

1/2v^2=Δxgu (horizontal direction)

Thanks for everyone else posting questions!
 

1. What is the formula for solving for distance using only initial velocity and coefficient of friction?

The formula for solving for distance using only initial velocity and coefficient of friction is: d = (vi)2 / 2μg, where d is the distance, vi is the initial velocity, μ is the coefficient of friction, and g is the acceleration due to gravity.

2. How do you determine the coefficient of friction for a given surface?

The coefficient of friction for a given surface can be determined through experimentation. This involves measuring the force required to move an object across the surface at a constant velocity and dividing it by the normal force (the force perpendicular to the surface). This process can be repeated with different masses to obtain an average value for the coefficient of friction.

3. Can this formula be used for objects moving on inclined surfaces?

Yes, this formula can be used for objects moving on inclined surfaces as long as the coefficient of friction used is the static coefficient of friction, which is relevant for objects at rest or in motion with a constant velocity on an inclined surface.

4. Does this formula take into account air resistance?

No, this formula does not take into account air resistance. It assumes that the object is moving through a vacuum or a medium with negligible resistance. If air resistance is significant, it must be accounted for separately in the calculation.

5. What are some practical applications of this formula?

This formula can be used in various real-world scenarios, such as calculating the stopping distance of a car on a particular surface, determining the maximum distance a ball can be kicked on a soccer field, or predicting the distance a projectile will travel before hitting the ground. It can also be applied in engineering and design to optimize the performance of machinery and vehicles.

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