Mass on incline plane sliding into spring, need to find max compression

In summary, the conversation discusses the problem of finding the maximum compression of a spring after an 11 kg block slides down a 4.0 m frictionless ramp and collides with the spring. The angle of the ramp is 30° and the spring has a spring constant of 190 N/m. The equations used to solve the problem are Ei=mgh and Ef=1/2kx^2, and the solution is found to be Xmax=1.8m.
  • #1
BryceHarper
15
0

Homework Statement



A 11 kg box slides 4.0 m down the frictionless ramp shown in the figure , then collides with a spring whose spring constant is 190 N/m. The angle of the ramp is 30°. What is the maximum compression of the spring?


Homework Equations



Ei=mgh
Ef=1/2kx^2

The Attempt at a Solution



Ei=Ef
mgh=1/2kx^2
mgLsinθ=1/2kx^2
11(9.8)(4sin30)=1/2(190)x^2
1.5m = Max compression

I swear this is right but it's not, can anyone help me out?
 
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  • #2
Is the spring laying on the ramp, or is there a flat part before the mass hits the spring, making the spring horizontal?

Also, does the 4m refer to the distance it slid along the ramp, or the vertical displacement?
 
  • #3
The spring is laying on the ramp and the 4m refers to the distance it slid along the ramp.
 
  • #4
You made the statement that the energy of the block 4 meters above the uncompressed spring is equal to the energy of the compressed spring, but that is leaving out a portion of energy.

From the point when the block is released to the time is stopped (at the maximum compression point of the spring) what is its change in height?
 
  • #5
Ohhhhhhhhh!

So i should do:
1/2(4+Xmax)sinθ=1/2k(Xmax)^2

?
 
  • #6
The left side should read 11(9.8) instead of (1/2), but besides that yes.
 
  • #7
Whoops! I guess I was so excited to have finally figured it out that I wrote the equation wrong lol.

To verify

mg(4+Xmax)sinθ=1/2k(Xmax)^2

So...

1/2k(Xmax)^2 - mgsinθ(Xmax) - mg4sinθ = 0

And then use quadratic equation to solve for Xmax?
 
  • #8
That looks right to me.

I wonder what the nature of the roots will be of that equation?
 
  • #9
Got it! Xmax is equal to 1.8m

Thanks for the help Villyer!
 
  • #10
Of course :smile:
 

1. What is the equation for finding the maximum compression of a spring?

The equation for finding the maximum compression of a spring is given by Hooke's Law: F = -kx, where F is the force applied to the spring, k is the spring constant, and x is the displacement of the spring from its equilibrium position.

2. How does the angle of the incline plane affect the maximum compression?

The angle of the incline plane affects the maximum compression by changing the gravitational force acting on the mass. As the angle increases, the gravitational force component parallel to the incline also increases, resulting in a greater force to compress the spring.

3. What other factors can affect the maximum compression of the spring?

Other factors that can affect the maximum compression of the spring include the mass of the object, the spring constant, and the coefficient of friction between the incline plane and the mass. These factors can all affect the net force acting on the mass on the incline and therefore the maximum compression of the spring.

4. How do you determine the maximum compression from a graph of force vs. displacement?

To determine the maximum compression from a graph of force vs. displacement, you can find the point where the slope of the graph changes from positive to negative. This indicates the point at which the force applied by the spring is no longer able to overcome the gravitational force, and the spring begins to compress.

5. Can the maximum compression of a spring be greater than the length of the spring itself?

Yes, the maximum compression of a spring can be greater than the length of the spring itself. This can happen if the mass on the incline plane has enough kinetic energy to continue compressing the spring even after it has reached its natural length. However, this is not a common occurrence and usually requires a very high initial velocity or a very stiff spring.

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