Other sets by this creator
A solar flux of is incident on a flat-plate solar collector used to heat water. The area of the collector is , and 90% of the solar radiation passes through the cover glass and is absorbed by the absorber plate. The remaining 10% is reflected away from the collector. Water flows through the tube passages on the back side of the absorber plate and is heated from an inlet temperature to an outlet temperature . The cover glass, operating at a temperature of , has an emissivity of 0.94 and experiences radiation exchange with the sky at . The convection coefficient between the cover glass and the ambient air at is . (a) Perform an overall energy balance on the collector to obtain an expression for the rate at which useful heat is collected per unit area of the collector, . Determine the value of . (b) Calculate the temperature rise of the water, , if the flow rate is 0.01 kg/s. Assume the specific heat of the water to be . (c) The collector efficiency is defined as the ratio of the useful heat collected to the rate at which solar energy is incident on the collector. What is the value of ?
An Atwood machine is used in a stage production to make an actress appear to fly up and out of view of the audience. The system consists of a actress and a sandbag connected via a rope over a pulley. The sandbag is released from rest. Determine the magnitude of the acceleration for both the actress and sandbag. Assume the rope and pulley are massless.