Convert Change in Temp from Celsius to Fahrenheit

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SUMMARY

The discussion focuses on converting temperature changes from Celsius to Fahrenheit in the context of Joule's experiments on the mechanical equivalent of heat. The participants calculated the expected rise in temperature of water using the formula for work done, arriving at a change of approximately 0.00982°C. However, the conversion to Fahrenheit was incorrectly attempted using an arbitrary factor of 33.8, rather than the correct conversion ratio of 180°F for every 100°C. The correct approach involves using the established conversion formula for temperature differences.

PREREQUISITES
  • Understanding of basic physics concepts, specifically mechanical work and energy transfer.
  • Familiarity with the formula for converting Celsius to Fahrenheit.
  • Knowledge of Joule's experiments and the mechanical equivalent of heat.
  • Basic arithmetic skills for calculations involving temperature changes.
NEXT STEPS
  • Research the formula for converting Celsius to Fahrenheit: Δ°F = (Δ°C × 9/5) + 32.
  • Explore Joule's experiments and their significance in thermodynamics.
  • Learn about the specific heat capacity of water and its implications in thermal energy calculations.
  • Investigate common mistakes in unit conversions and how to avoid them in physics problems.
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Students studying physics, educators teaching thermodynamics, and anyone interested in understanding temperature conversions and energy transfer principles.

Sondra
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Homework Statement


Consider the apparatus that Joule used in his experiments on the mechanical equivalent of heat, shown in the figure below. Suppose both blocks have a mass of 0.69 kg and that they fall through a distance of 0.45 m.

Homework Equations


(a) Find the expected rise in temperature of the water given that 6200 J are needed for every 1.0° C increase. Give your answer in Celsius degrees.
(b) Find the rise in temperature in Fahrenheit degrees.

The Attempt at a Solution


a) Work=2blocks (mgh) = 6.086J
Change in temp= W(1 celsius/6200J)= 9.82e-3
b) I tried converting 1 celsius to fahrenheit so my equation was:
Change in temp= W(33.8/6200J) = 0.033 F but that isn't correct.
I don't know how to do this part of the problem. Any and all help is appreciated
 
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Hi Sondra, Welcome to Physics Forums!

Your part (a) work done looks good (provided that I'm interpreting the question properly without seeing the figure), but check your temperature change value; it looks like your order of magnitude may be off.

You should be able to find the Celsius to Fahrenheit conversion formula with a quick Google search.
 
Sondra said:

Homework Statement


Consider the apparatus that Joule used in his experiments on the mechanical equivalent of heat, shown in the figure below. Suppose both blocks have a mass of 0.69 kg and that they fall through a distance of 0.45 m.

Homework Equations


(a) Find the expected rise in temperature of the water given that 6200 J are needed for every 1.0° C increase. Give your answer in Celsius degrees.
(b) Find the rise in temperature in Fahrenheit degrees.

The Attempt at a Solution


a) Work=2blocks (mgh) = 6.086J
Change in temp= W(1 celsius/6200J)= 9.82e-3
You might want to check your arithmetic here.
b) I tried converting 1 celsius to fahrenheit so my equation was:
Change in temp= W(33.8/6200J) = 0.033 F but that isn't correct.
I don't know how to do this part of the problem. Any and all help is appreciated

It's not clear what the factor 33.8 represents.

Also, you should know that 100 celsius degrees = 180 fahrenheit degrees (these are the difference in temperatures between freezing water and boiling water measured in the two scales.)
 
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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