Solving for the velocity of a Pendulum

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The discussion centers on calculating the speed of a 2 kg pendulum at the bottom of its swing after being released from an angle of 53 degrees. Two potential answers, 6.2 m/s and 40 m/s, are debated, with the correct speed depending on the pendulum's length and initial height. The importance of showing the working and the initial height is emphasized, as it affects the final calculation. It is suggested that if the height is around 2 m, the speed would likely be 6.2 m/s. Variations in answers may arise from different values used for gravitational acceleration.
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Homework Statement
A 2 kg pendulum is raised to an angle of 53 degrees relative to the vertical, as shown below, and released from rest. What is the speed of the mass at the bottom of its swing?
Relevant Equations
6.2 m/s
60 m/s
10 m/s
7.7 m/s
40 m/s
I think the answer is 6.2 but I also got 40m/s. Which one is right?
 
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momoneedsphysicshelp said:
Homework Statement:: A 2 kg pendulum is raised to an angle of 53 degrees relative to the vertical, as shown below, and released from rest. What is the speed of the mass at the bottom of its swing?
Relevant Equations:: 6.2 m/s
60 m/s
10 m/s
7.7 m/s
40 m/s

I think the answer is 6.2 but I also got 40m/s. Which one is right?
Depends on the length of the pendulum.
Please post your working.
 
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Also, please post the picture that is supposed to be "shown below". Maybe it shows the initial height above the lowest point of the swing. If it's 2 m (as I suspect), the correct answer for the speed is (a). Answer (e) is included to catch those who forget to take the appropriate square root. Answers may vary slightly depending on what number you use for the acceleration of gravity.
 
Last edited:
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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