What is the Spring Constant for Question 9?

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In summary: Then integrate k*X from X= 0 to X= 3.2 to find the work done.In summary, the conversation discusses two questions involving displacement, force, and work. In question 8, the speaker obtained a displacement of 3.2mm while the book stated 2.2mm. The only difference was the ball rebounding at 9.5ms-1 instead of compression. In question 9, the speaker explains their process of obtaining 3.2mm displacement and the confusion with the book's answer. They mention using the equation Work = Force * distance and integrating to find the work done. The conversation ends with the speaker asking for clarification on the slope of the force versus displacement graph.
  • #1
Cummings
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http://cummingsiam.steven-sst.com/argh.jpg [Broken]

question 8 is similar to my last forces question. I got 3.2mm displacement for the raquet - yet the book says 2.2
The only difference i see is that the ball rebounds at 9.5ms-1 and instead of compression - we have displacement. Its the same thing...

question 9 is damnright confusing..
 
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  • #2
How did you go about getting 3.2mm? Please post your work so we can check where your (or the book's) mistake is.

For the second one, remember Work = Force * distance. You'll need to do a few simple integrations.
 
  • #3
well,

the speed the ball is traveling is 10ms-1
the rule for kinetic energy is .5 * mass * velocity squared.
so .5 * .1 * 100
= 5j of energy

now, work done is measured in jouls.. and can be measured as the area under the force displacement graph.
so 5j = .5 * force * displacement.
if we let X = force and displacement
5j = .5Xsquared
10 = X squared
X = 3.2 mm displacement.

i let X = both force and displacement as if i change the scale of the force..X can equal both sides.

i get 3.2mm..the book says 2.2
 
  • #4
"if we let X = force and displacement"?

I don't know what you mean by "scale the force". What scale are you using? That should depend on the "spring constant"- the slope of the Force versus displacement graph. Unfortunately, I was unable to open your link to find that. What is the slope of the graph?
You should be able to write the force as k*X, reading k from the graph.
 

1. What are the two main types of forces?

The two main types of forces are contact forces, which require physical contact between two objects, and non-contact forces, which can act on objects without any physical contact.

2. What is the difference between balanced and unbalanced forces?

Balanced forces are equal in strength and opposite in direction, resulting in no change in an object's motion. Unbalanced forces are unequal in strength or direction, causing an object to accelerate or change its motion.

3. How do forces affect an object's motion?

Forces can cause an object to speed up, slow down, change direction, or stay at rest. The net force acting on an object determines its overall motion.

4. Can forces cancel each other out?

Yes, forces can cancel each other out if they are equal in strength and opposite in direction. This results in a net force of zero and no change in an object's motion.

5. How can we measure the strength of a force?

The strength of a force can be measured using a force meter, also known as a spring scale. The reading on the scale indicates the amount of force being applied to it.

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