The voltage detected by a radio is modeled as a random variable Y. When there is no transmit signal, the voltage is uniformly distributed between -2V and 2V. When there is a transmit signal, the voltage is between 0V and 3V.
dispersed properly. Suppose a signal is transmitted with probability 0.75 (or no signal transmitted with probability 0.25).
a. Find the probability density function of Y.
b. If the sensed voltage is Y = 1.5V, find the probability that the transmit signal will reach its location.

The y form of iron is known as: a) ferrite b) cementite c) perlite d) austenite

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

To save energy, the air supply to a 2000 ft office has been shut off overnight and the room temperature has dropped to 40°f. in the morning, the thermostat is reset to 70°f and warm air at 120 f begins to flov in at 200ft'/min. the air is well mixed within the room, and an equal mass flow of air at room temperature (changing with time) is withdrawn through a return duct. the air pressure is nearly 1 atm everywhere. ignoring heat transfer with the surroundings and kinetic and potential energy effects, estimate how long it takes for the room temperature to reach 70°f. plot the room temperature as a function of time.