Help on inelastic problem

  • Thread starter psruler
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In summary, the conversation is about finding the change in kinetic energy when a rubber ball is dropped elastically from a height of 2m and its velocity is 6.26m/s. The formula used is KE = 1/2mv^2 and the final answer is 0 joules, which makes sense since this is an elastic collision and energy is conserved.
  • #1
psruler
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Hi!

How do i find change in kinetic energy?

Here is the problem:
The rubber ball is dropped 2m elastically off the floor, so its speed immediately after bouncing is the same as immediately b4.
If the rubber ball has a mass of 0.015kg and its velocity is 6.26m/s, what is its change in kinetic energy from immediately b4 the collision to immediately after the collision? Breifly justify your answer.

Do i use this equation, KE = 1/2mv^2?

THANKS!
 
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  • #2
Yup. Change in kinetic energy is just the kinetic energy after minus the kinetic energy before.

So KE = 1/2*mv^2, now if m is the same for both and v is the same for both...

cookiemonster
 
  • #3
So is my answer, 0.29N?
 
  • #4
Hold on now!

1/2(.015kg)(6.26m/s)^2 - 1/2(.015)(6.26m/s)^2 = ?

Also, what units do you get? Here's a hint: it's not Newtons! It's kinetic energy, so its units will probably be energy.

cookiemonster
 
  • #5
I got 0 joules.
 
  • #6
Yup. And this makes sense, too, since this collision is elastic. Elastic collisions are collisions in which energy is conserved, so energy before had better equal energy after (and their difference had better equal zero)!

cookiemonster
 

1. What is an inelastic problem?

An inelastic problem is a situation where the quantity or volume of a substance or material remains constant, even when there are changes in the external forces or conditions acting on it. This means that the substance does not exhibit any significant change in shape, size, or volume in response to these external factors.

2. What causes inelasticity in materials?

Inelasticity in materials can be caused by a variety of factors, such as strong intermolecular forces, a rigid atomic or molecular structure, or the presence of impurities or defects in the material. These factors can prevent the material from undergoing significant changes in shape or volume when subjected to external forces.

3. How do you solve an inelastic problem?

The approach to solving an inelastic problem will depend on the specific situation and the type of material involved. In general, it involves analyzing the forces and conditions acting on the material, and understanding its properties and behavior under those conditions. Mathematical and computational models can also be used to predict the behavior of inelastic materials.

4. What are some real-life examples of inelastic problems?

Inelastic problems are commonly encountered in materials science and engineering, as well as in fields such as geology and environmental science. Some examples include the deformation of metals under high pressure, the flow of granular materials such as sand or soil, and the behavior of geological formations under stress.

5. How does inelasticity affect the properties of materials?

Inelasticity can have a significant impact on the mechanical, thermal, and electrical properties of materials. For example, inelastic materials may have lower strength and stiffness, higher thermal expansion, and lower electrical conductivity compared to elastic materials. Understanding and controlling inelastic behavior is important for designing and using materials in various applications.

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