Elastic Collision: Kinetic Energy and Spring Compression

In summary: Also, for the second part, use conservation of energy again: 1/2 mv2=1/2 kx2, where x is the distance the spring is compressed or bent.In summary, the problem involves a 50kg boulder sliding down a 5m high, 20m long hill against a friction force of 40N. At the top of the hill, the boulder is moving at 2m/s. It then slides on a horizontal frictionless surface and collides with a tree with a spring constant of 5000N/m. The task at hand is to find the kinetic energy at the bottom of the incline and the distance the spring/tree is compressed or bent when the boulder stops
  • #1
geauxKTM
6
0
Elastic collision, I think?

Homework Statement

50kg boulder slides down a 5m high, 20m long hill against friction force 40N. At the top the boulder is moving at 2m/s. At the base of hill the boulder slides on a horizontal frictionless surface for a short distance and then collides with a tree having spring constant 5000N/m. A. Find the kinetic energy at the bottom of the incline. B. find distance the spring(tree) is compressed or bent when the boulder stops



Homework Equations

Ff=40N m=50 V0=2 I am lost. For B f=kx right?



The Attempt at a Solution

No attempt and I have 3 of the smarter students sitting with me so please help. I seem to always receive feedback too late and I realize this is a weak attempt but I do have at least 4 more to post with a better understanding
 
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  • #2


Use conservation of energy. What is the total energy at the top? What is the work done by friction? When you get these two, you can get the kinetic energy at the bottom.
 
  • #3


rock.freak667 said:
Use conservation of energy. What is the total energy at the top? What is the work done by friction? When you get these two, you can get the kinetic energy at the bottom.

Thank you very much, is this right?. A.Ui+W=Kf (50(9.8)5)+(40*20)=3250J
B. 3250=500x^2
 
  • #4


Your equation should be mgh=1/2 mv2+Ffrictiond. Not sure which quantities were represented by your symbols.
 

1. What is an elastic collision?

An elastic collision is a type of collision in which kinetic energy is conserved. This means that the total amount of kinetic energy before the collision is equal to the total amount of kinetic energy after the collision.

2. How is an elastic collision different from an inelastic collision?

In an inelastic collision, kinetic energy is not conserved and is lost in the form of heat, sound, or deformation. In an elastic collision, however, kinetic energy is fully conserved.

3. Can you give an example of an elastic collision?

One example of an elastic collision is when two billiard balls collide. As long as there is no friction, the total kinetic energy of the two balls before and after the collision will be the same.

4. What is the equation for calculating the final velocities in an elastic collision?

The equation for calculating the final velocities in an elastic collision is: v1f = (m1-m2)/(m1+m2) * v1i + (2*m2)/(m1+m2) * v2i and v2f = (2*m1)/(m1+m2) * v1i + (m2-m1)/(m1+m2) * v2i, where v1f and v2f are the final velocities of the two objects, m1 and m2 are the masses of the two objects, and v1i and v2i are the initial velocities of the two objects.

5. What is the importance of elastic collisions in physics?

Elastic collisions are important in physics because they demonstrate the conservation of energy and momentum. They also allow us to understand and predict the behavior of objects in motion, which is essential in many fields of science and engineering.

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