3. The figure to the right depicts the experiment that James Prescott Joule of heatused to show the equivalencyand mechanical work. Equal masseswere placed on each pan, which createda force that is labeled "W" in thediagram. (Even Joule had troublekeeping mass and weight straight.)During the experiment, the mass wasallowed to drop a measured distance.The masses were connected to paddlesvia a wire and pulley system. Thepaddles stirred a sample of water. Joule would then measure the temperature rise in the water. Joule insulatedthe water beaker, but initially assumed that the heat absorbed by thepaddles was negligible.

b. What assumptions did you make in reaching the value you reported inPart a? c. Please compare your answer in Part a to the accepted value of 778 ft-lbf/lbm-°R. I.e., what is thepercent error? d. Joule presented his work to the Royal Society in 1845. The RoyalSociety declined to publish his work in part because he neglected the heatabsorbed by the paddles.* Joule's then conducted a set of experiments inwhich he varied the mass of water and then adjusted the length of theweight drop to give a constant temperature change. He was then able toeliminate the effect of heat absorbed by the paddles. In his second paperbefore the Royal Society, in 1850, he reported a much better value of 772lbf/lbm-ºR, (the value inscribed on his head stone). How was Joule able toobtain a better result from his experimental protocol?