Determine the activation energy for diffusing copper into gold if you know that the diffusion coefficient is 3.98 x 10-13 m2/s at 980 degreec and the diffusion coefficient is 3.55 x 10-16 m2/s at 650degreec.

At steady state, air at 200 kpa, 325 k, and mass flow rate of 0.5 kg/s enters an insulated duct having differing inlet and exit cross-sectional areas. the inlet cross-sectional area is 6 cm2. at the duct exit, the pressure of the air is 100 kpa and the velocity is 250 m/s. neglecting potential energy effects and modeling air as an 1.008 kj/kg k, determine ideal gas with constant cp = (a) the velocity of the air at the inlet, in m/s. (b) the temperature of the air at the exit, in k. (c) the exit cross-sectional area, in cm2

Two slings are used to lift a girder of length l and uniform weight per unit length. what is the best position for the slings if the bending moment due to the weight of the girder is to be kept to a minimum?

Different between right hand turning tool and left hand turning tool ?