The following details are known about a 150 hp motor, 240 V, 500 rpm, dc shunt motor. Nominal full load current: 500 A Insulation class: H Weight: 3400 kg

Find

1.The total losses and efficiency at full load.

2.Calculate the approximate shunt filed exciting current if the shunt field causes 20% of the total losses.

3.Calculate the value of the armature resistance knowing that 50% of the total losses at full load are due to armature resistance.

4.With your calculated armature resistance, determine the counter-emf.

5.Determine the torque of the motor at full load.

6.The supply voltage is decreased to 200 V, approximate the speed at this supplied voltage.

Let the market for cigarettes be characterized by the following information: Qd70-5P Demand] Qs= 3P-10 [Supply] Suppose the government imposes a sales tax of S1.50 per unit. Answer questions (i) through (v) below: i) [10 points] Calculate the magnitude of the consumer surplus and producer surplus in the pre-tax equilibrium Calculate the tax revenue in the post-tax equilibrium. Calculate the change in consumer surplus due to the sales tax. Calculate the change in producer surplus due to the sales tax. Calculate the Dead-Weight-Loss due to the sales tax. ii) [10 points) iii) [10 points] iv) [10 points] v) [10 points

Type the answers to be clear

Think of a research idea in which you will compare 2 groups (sample v population or sample v sample) on some variable (e.g., the book uses the example of the IQ of a particular group vs. the IQ of the general population—do not use this example). Answer all of the following questions for this study.

Study

a) What are your two groups?

b) What is the variable you will test?

c) State your null hypothesis using the formula notation shown in the book.

d) State your alternative hypothesis using the formula notation shown in the book.

e) In sentence structure state your alternative hypothesis.

f) Based on your hypothesis is your study one- or two-tailed?

A 2000 V single-phase synchronous generator is being used as a backup
generator outside a diagnostic center. When the generator
terminals are short-circuited and a field excitation current of 2.5 A is passed, the
ammeter between the terminals read 100 A of full load current. If the terminals
of the same generator are opened and the voltage across them is measured using
a voltmeter, we get the value of 500 V with the same excitation current. The
armature resistance is 0.8 ohms.
Determine the voltage regulation of this generator if it is delivering 100 A
during normal operation with unity power factor, 100 A with 0.8 leading PF,
and with 0.71 lagging PF.
(Hint: Synchronous Impedance = (0.C Voltage) / (S.C Current))

Huffman codes T/F Questions:

Q1 : Let s be the depth of the leaf with the smallest depth (i.e. closest to the root) in an optimal prefix-free code tree T. Then the highest frequency character has depth s in T. (Assume frequencies are distinct.) T or F

Q2 : Let T be an optimal prefix-free code tree, and let v be any non-leaf node in T. If we exchange the left and right subtrees of v (i.e. swap its left and right child pointers) then the resulting new tree must still be an optimal prefix-free code tree. T or F

Please explain why it's either T or F

In class we discussed the disputed election that ended up in the case DeMartini v. Power, 262 NE2d 857. A similar case (Ipolito v. Power 241 NE2d 232) had one candidate receiving 1422 votes and the other 1405 votes. After the election, it was determined that 101 ineligible voters had voted. (a) What is the probability that the outcome of the Ipolito election would change if 101 votes were removed at random? (In this part, leave your answer as a sum involving binomial coefficients.) (b) Write a python 3 program to compute the probability given in the previous part. (c) If you were the appelate court judge, would you rule that the vote should be redone or not? Why?

1. A 440 V 4-pole 3 phase 50 Hz slip ring induction motor has its stator winding mesh connected and its rotor winding star connected. The standstill voltage measured between slip rings with the rotor open –circuited is 218 V. the stator resistance per phase is 0.6Ω and the stator reactance per phase is 3Ω. The rotor resistance per phase is 0.05Ω and the rotor reactance per phase is 0.25Ω. Calculate the maximum torque and the slip at which it occurs. If the ratio of full-load to maximum torque is 1:2.5 find the full-load slip and the power output. [s_max =0.1; T_max= 278 Nm; s=0.02; P=17.1 kW]

Assume that there are 2 firms locating in Hotelling’s linear city of length 1. Each firm has a constant marginal cost of c. Consumers are uniformly distributed and have identical preferences represented by U=V-Pi-t(x*-xi)2 . where V-is consumer’s reservation value (consumer surplus from consuming her ideal product at zero price), Pi is the price of firm i’s product, x* is consumer’s location, 0≤x 1 and xi is firm i’s location. a) If both firms are required to locate in the middle, what price would they charge? b) If both firms are required to locate at two different ends of the city what price will they charge?

Question 6. There are two bidders in a sealed-bid, second-price auction. The object for sale has a common value. Each bidder, i = 1,2, receives a signal i that is independently and uniformly distributed on the interval [0, 1]. The true value of the object, v, is the average of the two signals,

v = (σ1 + σ2) / 2

(a) If bidder 1 gets the signal σ = 0.7, how much does he think the object is worth?

(b) Suppose that each bidder submits a bid equal to the expected value of the object (conditional on his signal). If bidder 1 submits the winning bid, what is the expected value of the object?

(c) What is the expected surplus for bidder 1 under the assumptions in (b)?