Question

Thermal Efficiency Internal Heat Energy AQ (J) Energy Lost (1) Material Work (J) Thermal Efficiency (%) Aluminum 89.89 63.55 26.34 70.70 Brass 49.09 39.74 9.35 80.95 3.) Show your work. Aluminum Energy Lost-89.89-63.55=26.34 J Aluminum Thermal Efficiency (%). e=q/w = 63.55/89.89x100=70.70% Friction Heating - 5 Brass Energy Lost- 49.09-39.74=9.35J Brass Thermal Efficiency..(%)-e=q/w = 39.74/49.09 x100=80.95%

Answer 1

(a) the equation of power used is

  

Power = force applied x distance to which mass is lifted time taken

(b) Aluminium is a metal while brass is an alloy. So aluminium has higher number of free electron. Also the heat capacity of Brass is lesser than aluminium which means to raise temperature we need less energy for brass. But it also depends upon mass and density of specimen. The change in temperature causes change in internal energy. Since aluminium is a metal and hence it has more free electron so on heating they gains more kinetic energy and henece suffers collision at a faster rate. Due to these collision energy is lost in the form of heat.

(c) The thermal efficiency is not 100% because the all the work done on system is not used to increase its internal energy some part of work done is lost in the form of heat energy. This energy is released into atmosphere and hence rise the local temperature causing convection in surrounding air.

(d) This experiment is important because it tells us for which substance energy loss will be minimum and which material requires higher amount of heat. aluminium is generally used for cooking due to its high specific heat.