Physics Problem with Spring Constant and Kinetic Friction

In summary, the conversation discusses finding the ratio of the spring constant to the kinetic friction coefficient when a spring is attached to a 36kg object and pulled along a table at a steady speed of 1.3m/s with a spring stretch of 3.4cm. The relationship between F, Fk, and Fspring is also explored, and the final answer is 10,376.47 N/m per unit of μk.
  • #1
Q7heng
10
0

Homework Statement


A person attaches a spring to an cubic object that weighs 36kg and pulls this object along a table made of material X horizontally with a steady speed of 1.3m/s. The spring stretches a distance of 3.4cm. Find the ratio of the spring constant to the kinetic friction coefficient.

Homework Equations


I suppose FkkN
Fspring=-kx
F=ma
Not sure if any other ones are needed, but I couldn't find a way to solve this and get a reasonable answer.
 
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  • #2
Q7heng said:
steady speed of 1.3m/s
What does this information tell you?
 
  • #3
Bystander said:
What does this information tell you?
I'm not sure, but I tried to apply it to the F=MA formula... Am I on track?
 
  • #4
Q7heng said:
I'm not sure, but I tried to apply it to the F=MA formula... Am I on track?
Okay, we'll work it through that way: "Steady speed" means what in terms of "A?"
 
  • #5
Bystander said:
Okay, we'll work it through that way: "Steady speed" means what in terms of "A?"
Acceleration=0 at steady speed, but the trouble I'm having is converting everything to Newtons, since spring constant is Newtons/meter, and kinetic friction coefficient is Force of Kinetic Friction/Normal Force. The problem didn't give any units related to those calculations, maybe there is a way to convert it but I have yet figured it out/learned it.
 
  • #6
Q7heng said:
I suppose Fk=μkN
This looks perfectly useful. What's the normal force?
Q7heng said:
Fspring=-kx
Nothing wrong with this.
You aren't required to generate a numerical answer for every problem on the planet. Sometimes it's just a matter of coming up with a symbolic expression.
 
  • #7
Q7heng said:
Acceleration=0
FkkN
Fspring=-kx
F=ma
All good so far. Now, what is the relationship between F, Fk and Fspring?
 
  • #8
haruspex said:
All good so far. Now, what is the relationship between F, Fk and Fspring?
F=Fk+Fspring right?
If that is so then:
F=MA, A=0, and F=0
So 0=Fk+Fspring
0=-kx+μkN
kx=μkN
k/μk=N/x, since we are trying to find the ratio between the spring constant and the kinetic friction coefficient
Since N, normal force, is 36*9.8N right now, and x, distance, is 3.4cm or 0.034m right now, then it is 36*9.8/0.034=10,376.47, which is the ratio of spring constant to kinetic friction, is that correct?
 
  • #9
Q7heng said:
F=Fk+Fspring right?
If that is so then:
F=MA, A=0, and F=0
So 0=Fk+Fspring
0=-kx+μkN
kx=μkN
k/μk=N/x, since we are trying to find the ratio between the spring constant and the kinetic friction coefficient
Since N, normal force, is 36*9.8N right now, and x, distance, is 3.4cm or 0.034m right now, then it is 36*9.8/0.034=10,376.47, which is the ratio of spring constant to kinetic friction, is that correct?
Yes, that all looks right. But you should include the units in the answer.
 
  • #10
Thanks!
 

Related to Physics Problem with Spring Constant and Kinetic Friction

1. What is the formula for spring constant?

The formula for spring constant, also known as force constant, is k = F/x, where k is the spring constant, F is the applied force, and x is the displacement of the spring.

2. How do you calculate the force exerted by a spring?

The force exerted by a spring can be calculated by multiplying the spring constant (k) by the displacement of the spring (x). So, F = kx.

3. How does kinetic friction affect a spring's oscillation?

Kinetic friction, or the friction between two surfaces in motion, can affect a spring's oscillation by reducing the amplitude of the oscillation. This is because kinetic friction converts some of the energy of the oscillation into heat, causing the spring to lose energy and decrease in amplitude over time.

4. Can the spring constant change?

The spring constant is a physical property of a spring and is determined by the material and shape of the spring. In most cases, the spring constant does not change, but it can be altered by changing the material or shape of the spring.

5. How is the spring constant related to the stiffness of a spring?

The spring constant is directly related to the stiffness of a spring. A higher spring constant indicates a stiffer spring, meaning it requires more force to produce a certain amount of displacement. Similarly, a lower spring constant indicates a less stiff spring.

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