Spring constant/kinetic energy

In summary, the conversation discusses how to calculate the reading on a bathroom scale when jumping on it from a certain height. The key equations used are F=kx, K.E=1/2mv^2, and Eep = 0.5 kx2. The process involves finding the spring constant, calculating the total energy of the system, and using it to determine the compression (x) at the peak. Finally, this value is substituted into F=kx to find the scale reading.
  • #1
kavipach
20
0

Homework Statement



If you stand on a bathroom scale, the spring inside the scale compresses 0.55mm, and it tells you your weight is 760 N.
Now if you jump on the scale from a height of 1.3m, what does the scale read at its peak?

Homework Equations


F=kx
K.E=1/2mv^2


The Attempt at a Solution


I tried a lot of things but i can't get the answer
 
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  • #2
I tried a lot of things but i can't get the answer
Try more... :smile:

Well one more equation you need to know

Elastic potential energy = Eep = 0.5 kx2

I'm sure you know how to get the spring constant, k
And then find the total energy of the system E = mgh

then substitute the E value you got to the equation
Eep = 0.5 kx2 to find x

(at the "peak", all of the kinetic energy + gravitational potential energy is converted to elastic potential energy)

then since you know the x (compression) at the peak value
substitute to F = kx to get the F value for the scale value it reads

That's what i would do.
I can very well be wrong
 
  • #4
Very well explained, V_B!
 
  • #5
Thx LOL ^^
 

1. What is the definition of "spring constant"?

The spring constant, also known as the force constant, is a measure of the stiffness of a spring. It is defined as the force required to stretch or compress a spring by a certain distance.

2. How is the spring constant calculated?

The spring constant is calculated by dividing the applied force by the resulting displacement of the spring. It is expressed in units of force per unit of distance, such as N/m or lb/in.

3. What is the relationship between spring constant and potential energy?

The potential energy stored in a spring is directly proportional to the spring constant. This means that a higher spring constant results in a greater amount of potential energy stored in the spring when it is compressed or stretched.

4. How does the spring constant affect the period of a spring-mass system?

The period, or time it takes for one complete oscillation, of a spring-mass system is inversely proportional to the square root of the spring constant. This means that a higher spring constant will result in a shorter period.

5. What is the difference between spring constant and kinetic energy?

Spring constant is a measure of the stiffness of a spring, while kinetic energy is the energy an object possesses due to its motion. Although the two concepts are related in the case of a spring-mass system, they are not interchangeable.

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