Practice Problem about the Energy of a Pendulum

Thread starter stephy
Start date May 17, 2021
Tags

Energy Pendulum

AI Thread Summary

The discussion centers on a practice problem regarding the energy of a pendulum, with initial answers provided as 7.35 m/s for speed and 216.09 m/s² for acceleration. Participants emphasize the importance of showing work and reasoning behind the calculations to facilitate better assistance. There is a suggestion to consider energy principles for solving the problem. The conversation highlights the need for detailed explanations rather than just final answers. Overall, the focus is on understanding the underlying concepts of pendulum energy.

May 17, 2021

stephy

Homework Statement: A small sphere of mass m is fastened to a weightless string of length 0.5m to form a pendulum. The pendulum is swinging so as to make a maximum angle of 60 degrees with the vertical.
a) What is the velocity of the sphere when it passes through the vertical position?
b) What is the instantaneous acceleration when the pendulum is at its maximum deflection?

Relevant Equations: a) v=sqrt(L*g*sine(thet)*tan(thet)
b) ac= v^2/r

Answer:
a) 7.35 m/s
b) 216.09 m/s^2

*Is this correct?

Physics news on Phys.org

May 17, 2021

Orodruin

Staff Emeritus

Science Advisor

Homework Helper

Insights Author

Gold Member

2024 Award

It would be easier to offer you help if you offer a bit more detail for your reasoning.

In both of the cases a) and b), what is your argumentation behind the expressions?

May 17, 2021

phinds

Science Advisor

Insights Author

Gold Member

2024 Award

stephy said:

*Is this correct?

I suggest you read the forum rules, one of which is that you are required to show work (not just answers).

May 17, 2021

rsk

No working out offered by me (yet), but I would look at energy considerations for the first part.

Thread 'Power of a thin lens in a medium is 1/fₘ or μₘ/fₘ ?'

Here is what I tried This question was actually asked in one of our engineering entrances. The answer was 1D. My teachers say that we have to use μₘ/fₘ to get to this answer. I cannot understand why. I'll be really glad if you could tell me the exact definition of power (numerically) that works in all scenarios.

View full post »

Thread 'Voltmeter readings for this circuit with switches'

TL;DR Summary: I would like to know the voltmeter readings on the two resistors separately in the picture in the following cases , When one of the keys is closed When both of them are opened (Knowing that the battery has negligible internal resistance) My thoughts for the first case , one of them must be 12 volt while the other is 0 The second case we'll I think both voltmeter readings should be 12 volt since they are both parallel to the battery and they involve the key within what the...

View full post »

Thread 'Struggling to make relation between elastic force and height'

Hello guys this is what I tried so far. I used the UTS to calculate the force it needs when the rope tears. My idea was to make a relationship/ function that would give me the force depending on height. Yeah i couldnt find a way to solve it. I also thought about how I could use hooks law (how it was given to me in my script) with the thought of instead of having two part of a rope id have one singular rope from the middle to the top where I could find the difference in height. But the...

View full post »