# Electrical Engineering

## For each of the three mechanical systems illustrated in Figure 1, provide the differential equation relating the mass displacement, x(t), to the applied force, f(t). M is the mass in kg, K is the spring constant with units of N/m, and fv is the coefficient of viscous friction with units of Ns/m. ​

For each of the three mechanical systems illustrated in Figure 1, provide the differential equation relating the mass displacement, x(t), to the applied force, f(t). M is the mass in kg, K is the spring constant with units of N/m, and fv is the coefficient of viscous friction with units of Ns/m. ​ EXPERT ANSWER

## The current commercial Amplitude Modulation (AM) broadcast based radio stations operate in the 540 to 1700 KHz band with a transmission bandwidth of 10 KHz. What are the maximum number of stations that can be licensed to operate as an AM radio station? If we would like to completely minimize the interference produced by adjacent station (due to poor IF characteristics) in the above allocation and we don’t allow stations to be assigned in adjacent channels, then how many stations can be accommodated in the AM range? What are the possible image stations in the AM radio?

EXPERT ANSWER Question #1:Take 1700 kHz – 540 kHz to get the total bandwidth to be dividedup.1700kHz – 540kHz = 1160kHz Then divide by the bandwidth1160kHz / 10(kHz/station) = 116 stations Question #2:To avoid interference, we skip station spaces every otherspace.[station][–space–][station][–space–] etcTo do this, divide the number of stations by two since it there isan …

## In the lab, we performed nucleation experiments to predict the nucleation rate of an active pharmaceutical ingredient at two different initial supersaturations. Assume that we started the experiments with 17 vials. Table below shows the time versus the number of vials nucleated at the studied initial supersaturations.

In the lab, we performed nucleation experiments to predict the nucleation rate of an active pharmaceutical ingredient at two different initial supersaturations. Assume that we started the experiments with 17 vials. Table below shows the time versus the number of vials nucleated at the studied initial supersaturations. S = 2 S = 4 No of …

## The dimensionless Henry’s law constant for hexane is 0.14. A sealed glass vial is prepared that has an air volume of 5 ml overlying aqueous volume of 55 ml. Hexane is added to the aqueous phase so that initially it has an aqueous phase concentration of 0.2ppm. After the system equilibrates, what will be the concentration of hexane in the aqueous phase?

The dimensionless Henry’s law constant for hexane is 0.14. A sealed glass vial is prepared that has an air volume of 5 ml overlying aqueous volume of 55 ml. Hexane is added to the aqueous phase so that initially it has an aqueous phase concentration of 0.2ppm. After the system equilibrates, what will be the …

## A pressure cooker has the lid screwed on tight. A small opening with A = 5 mm2 is covered with a petcock that can be lifted to let steam escape. How much mass should the petcock have to allow boiling at 120oC with an outside atmosphere at 101.3 kPa?

A pressure cooker has the lid screwed on tight. A small opening with A = 5 mm2 is covered with a petcock that can be lifted to let steam escape. How much mass should the petcock have to allow boiling at 120oC with an outside atmosphere at 101.3 kPa? EXPERT ANSWER m = P*A/g m …