Pig on a slide Friction Problem

I did the algebra right, but I didn't check my arithmetic.)In summary, the coefficient of kinetic friction between the pig and the slide is 0.53. This was calculated using the distance down the ramp with and without friction, the acceleration with and without friction, and the time it takes to slide down the slide with and without friction. The final equation is μ = 3tanθ/4.
  • #1
Kharmon7814
7
0
A slide loving pig slides down a certin 35 degree slide in twice the time it would take to slide down a frictionless 35 degree slide. What is the coefficient of kinetic friction between the pig and the slide? Here is what I have so far...
[sum]Fx=ma=mgsin [the] -[mu]mgcos[the] I canceled out the mass on both sides and get
[sum]Fx=a=gsin [the] -[mu]gcos[the]

For the y forces I have
[sum]y=N=mgcos[the]

As far as the difference in the time with or without friction I have x=mgsin[the]=(1/2)a[tex]t^2[/tex] for the slide with no friction and I have x=mgsin[the]=2a[tex]t^2[/tex]for the slide with friction
This is all the info I have been able to come up with...I can't figure out how to put it all together. Thanks for helping. I've been working on this one for awhile.
 
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  • #2
Be careful about mixing up forces, accelerations and positions. For example, your second equation has forces equalling accelerations (not good). I'm assuming the 'x' direction is along the ramp and that the pig starts at the top of the ramp from rest (I'm told pigs like to rest). So let's call the distance down the ramp (same for friction/no friction) Δx. In either case,

[itex] \Delta x = \frac{at^2}{2} [/itex]

which is where (it seemed like) you were heading.

The acceleration is different in each case and the time is different in each case. Let's call the time down the frictionless slide T, and the time down the slide with friction 2T. From your force balance, you found the acceleration with friction already, let's call it af:

[itex] a_f = g\sin \theta - \mu g\cos \theta [/itex]

without friction (anf) is simply:

[itex] a_{nf} = g\sin\theta [/itex]

To put it all together, equate Δxf with Δxnf:

[itex] \frac{a_f(2T)^2}{2} = \frac{a_{nf}T^2}{2} [/itex]

substitute in your expressions for af and anf and solve for μ

[itex] 4\left(g\sin \theta - \mu g\cos \theta\right) = g\sin\theta [/itex]

[itex] \vdots [/itex]

[itex] \mu = 3\tan\theta [/itex]

(I suggest you verify my algebra for yourself in case I made a careless error or two.)


Edit:
(Last line corrected for algebra)

[itex] \mu = \frac{3\tan\theta}{4} [/itex]
 
Last edited:
  • #3
Thanks

Funny how it seems so obvious when someone explains it. Thanks for your help.
 
  • #4
Algebra Corrections

It turns out to be (3/4)Tan[the] I got the final answer to be [mu]=.53 Ahhhh, now I can sleep at night[zz)]
 
  • #5
Good job. Glad I put in that disclaimor; maybe I should just add it to my signature. I guess I was so wrapped up in using the new [itex] \LaTeX [/itex] functionality that I forgot to distribute the 4.
 

FAQ: Pig on a slide Friction Problem

What is friction and how does it affect the movement of a pig on a slide?

Friction is a force that acts to resist the relative motion between two surfaces in contact. In the case of a pig on a slide, friction is what allows the pig to slide down the surface. Without friction, the pig would not be able to move and would simply remain stationary on the slide.

How does the weight of the pig affect the amount of friction on the slide?

The weight of the pig does not directly affect the amount of friction on the slide. However, the weight does affect the normal force, which is the force exerted by the surface on the pig. This normal force, in turn, affects the friction force, as the friction force is directly proportional to the normal force.

Can the type of material on the slide affect the amount of friction?

Yes, the type of material on the slide can significantly affect the amount of friction. Smooth surfaces, such as plastic or metal, have less friction than rough surfaces, such as wood or sand. This is because smooth surfaces have less surface irregularities that create resistance to motion.

How does the angle of the slide impact the pig's movement?

The angle of the slide plays a crucial role in the pig's movement. The steeper the angle, the greater the gravitational force acting on the pig, which increases the normal force and therefore the friction force. This results in a faster slide down the surface. A shallower angle would result in less friction and a slower slide.

Can the pig's physical characteristics affect the amount of friction on the slide?

Yes, the pig's physical characteristics can impact the amount of friction on the slide. For example, a larger and heavier pig will have a greater normal force and therefore more friction than a smaller and lighter pig. Additionally, the texture of the pig's skin or fur can also impact the friction force as it interacts with the surface of the slide.

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