PASCO TD-8551A MECHANICAL EQUIVALENT OF HEAT - Manual (Page 11)

012-04331E Mechanical Equivalent of Heat
7
Data
Mass Hanging from Rope: M =__________________________
Mass of Aluminum Cylinder: m = _______________________
Radius of Cylinder: R = _______________________________
Number of turns of crank : N = _________________________
Calculations
Work performed on cylinder: W =
τ θ
= MgR(2
π
N) = __________________
Heat absorbed by cylinder: Q = mc (T
f
- T
i
) = ________________________
Mechanical Equivalent of Heat: J = W/Q = ___________________________
(Acceleration due to gravity: g = 9.8 m/s 2 ; Specific Heat of Aluminum: c = 0.220 cal/g
∞
C)
Suggested Questions
➀
Compare your value of J with the accepted value (check your textbook).
➁ Discuss any sources of error that you feel might have affected your results. Are some of these avoidable?
What affect would they have on your calculated value for J? Can you estimate the magnitude of the effects?
➂ Is it experimentally possible that the heat absorbed by the cylinder could be greater than the work performed
on it? Explain.
➃ Can your value of J be used for determining how much mechanical energy can be produced from a specified
amount of thermal energy? Why or why not?
Temperature (
∞
C) Corresponding Thermistor Resistance (
Ω
)
Room Temperature
Initial Temperature (T
i
)
Final Temperature (T
f
)
Ideal (pre-selected value)
Actual (Highest Temp)
T
f
- 1
∞
C
(Begin Slow Cranking)
Worksheet