Is 51 micro joules the maximum kinetic energy of this pendulum?

In summary, the conversation is discussing the calculation of the maximum kinetic energy of a pendulum based on given information such as time period and amplitude. The estimated value of 50.98 micro joules is deemed accurate, and it is recommended to include units in calculations. There is also a discussion on the precision of the given numbers and the need for additional information such as the definition of "amplitude" and the gravity field. The final suggestion is to round the estimated value to 51.0 micro joules.
  • #1
Bolter
262
31
Homework Statement
Calculate the maximum kinetic energy of the pendulum
Relevant Equations
angular speed = 2 pi/T

KE = 1/2mv^2
Screenshot 2020-02-25 at 17.47.25.png

So I have been given a question here which asks me to work out the maximum kinetic energy of the pendulum

It has given info such as time period and amplitude, which I had then made use of these formulas

IMG_3992.JPG


Does a kinetic energy of approx 50.98 micro joules seem right here?

Any help would be great! Thanks alot
 
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  • #2
I think it's okay (I didn't pay very much attention to the numbers). But if you were my student, I would highly recommend you to put always the units so, when computing ##v_{max}##, put
$$v_{max}=2.9 \text{ s}^{-1}\cdot 0.05 \text{m} = 0.14 \text{ms}^{-1}$$ and so on.
 
  • #3
Bolter said:
Homework Statement:: Calculate the maximum kinetic energy of the pendulum
Relevant Equations:: angular speed = 2 pi/T

KE = 1/2mv^2

View attachment 257680
So I have been given a question here which asks me to work out the maximum kinetic energy of the pendulum

It has given info such as time period and amplitude, which I had then made use of these formulas

View attachment 257681

Does a kinetic energy of approx 50.98 micro joules seem right here?

Any help would be great! Thanks alot
Looks about right.

You could calculate the answer using maximum potential energy to check it yourself.
 
  • #4
How is "amplitude" in centimeters defined? Is it the change in elevation, or is it an arc-length? Does the answer (max KE) depend on the gravity field (are we on the Earth or the moon)? I'm trying to figure out if we need those defined, or if period (which gives L/g) is sufficient to answer.
 
  • #5
Bolter said:
Does a kinetic energy of approx 50.98 micro joules seem right here?
You should not quote more significant figures than in your least precise input, so make it 51.
 

1. What is the maximum kinetic energy of a pendulum?

The maximum kinetic energy of a pendulum is equal to the potential energy at its highest point. This is because the potential energy is converted into kinetic energy as the pendulum swings downwards.

2. How is the maximum kinetic energy of a pendulum calculated?

The maximum kinetic energy of a pendulum can be calculated using the formula KE = 1/2 * m * v^2, where m is the mass of the pendulum and v is its velocity at the highest point.

3. How does the length of a pendulum affect its maximum kinetic energy?

The length of a pendulum does not affect its maximum kinetic energy. This is because the maximum kinetic energy is determined by the height of the pendulum's swing, which is only affected by the initial potential energy and the force of gravity.

4. Can the maximum kinetic energy of a pendulum be greater than its potential energy?

No, the maximum kinetic energy of a pendulum cannot be greater than its potential energy. This is because energy is conserved in a pendulum and the total energy (potential + kinetic) remains constant throughout its swing.

5. How does the mass of a pendulum affect its maximum kinetic energy?

The mass of a pendulum does not affect its maximum kinetic energy. This is because the maximum kinetic energy is determined by the height of the pendulum's swing, which is only affected by the initial potential energy and the force of gravity.

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