Aglass bulb with radius r = 15 cm is filled with water vapor at a temperature of t = 500 k. on the exterior of the bulb a spot with area a = 2.0 mm2 is placed in contact with liquid nitrogen. this causes the temperature of the spot to drop well below 0◦c. when the gaseous water molecules strike this area from inside they immediately freeze effectively removing them from the gas. determine how much time it takes for the pressure in the bulb to reduce to half its original value. assume the temperature of the gas in the container remains at 500 k

Abrake has a normal braking torque of 2.8 kip in and heat-dissipating cast-iron surfaces whose mass is 40 lbm. suppose a load is brought to rest in 8.0 s from an initial angular speed of 1600 rev/min using the normal braking torque; estimate the temperature rise of the heat dissipating surfaces.

Asingle-geared blanking press has a stroke of 200 mm and a rated capacity of 320 kn. a cam driven ram is assumed to be capable of delivering the full press load at constant force during the last 15 percent of a constant-velocity stroke. the camshaft has an average speed of 90 rev/min and is geared to the flywheel shaft at a 6: 1 ratio. the total work done is to include an allowance of 16 percent for friction a) estimate the maximum energy fluctuation b) find the rim weight for an effective diameter of 1.2 m and a coefficient of speed fluctuation of 0.10

Slip occurs via two partial dislocations because of (a) the shorter path of the partial dislocation lines; (b) the lower energy state through partial dislocations; (c) the charge balance.