answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
ruslelena [56]
2 years ago
15

Plutonium isotopes undergo decay, producing heat. Plutonium isotope 239 (Pu-239) has 1.9 watts per kilogram [W/kg] of decay heat

. How much heat, in units of calories [cal], will 1.25 moles [mol] of Pu-239 release after decaying for three hours [h]
Engineering
1 answer:
Sunny_sXe [5.5K]2 years ago
7 0

Answer:

1495.81 calories = 1500 calories to 2 s.f

Explanation:

1.9 Watts of decay heat is released for every kilogram of Pu-239 that decays.

1.25 moles of Pu-239 will release which amount of heat in 3 hours (calories)

First of, we calculate how much mass of Pu-239 is contained in 1.25 moles of Pu-239.

Molar mass of Pu-239 = 244 g/mol = 0.244 kg/mol

1.25 moles of Pu-239 = 1.25 × 0.244 = 0.305 kg

1 kg of Pu-239 is equivalent 1.9 Watts

0.305 kg of Pu-239 will give (0.305×1.9/1) Watts; 0.5795 Watts.

Note: Watts is J/s

Power = Energy/time

Energy = power × time

Power = 0.5795 Watts

Time = 3 hours = 3×3600 s = 10800 s

Energy = 0.5795 × 10800 = 6258.6 J

1 J = 0.239 calorie

6258.6 J = 6258.6 × 0.239 = 1495.81 calories

You might be interested in
Discuss your interpretation of the confidence-precision trade-off, and provide a few examples of how you might make a choice in
LenKa [72]

The given question is incomplete, the complete question is as follows:

Our text describes a trade-off that we must make as engineers between our confidence in the value of a parameter versus the precision with which we know the value of that parameter. That trade-off might be affected by whether we are looking at a two-sided or bounded (one-sided) interval.

Question: Discuss your interpretation of the confidence-precision trade-off, and provide a few examples of how you might make a choice in one direction or the other in an engineering situation.

Answer: A balancing point is required to be reached to obtain a better confidence level in the predicted values.

Explanation:

The confidence interval and precision are the two terms that aims at providing the accurate estimation of the measurability of an object. If the precision increases, we can compromise on the confidence level and if the confidence level increases, then the precision of the predicted value also dilutes.

Thus a balance point is required to be reached between these two variables so that we get better confidence in the values being predicted without losing the correct estimation on precision. Ensuring that both the confidence and precision are maintained.

8 0
2 years ago
John was a high school teacher earning $ 80,000 per year. He quit his job to start his own business in pizza catering. In order
Anton [14]

Answer:

John should continue with his catering business because accounting and economic profits from pizza catering are more than his annual salary from teaching.

Explanation:

John can earn from teaching $80,000 annually

For starting business of pizza catering John will incur following expense

Tuition for catering skills $2,000

Opportunity cost for withdrew of funds ($110,000 * 5%) $5,500

Interest for Borrowing from friend ($50,000 * 6%) $3,000

Opportunity cost of Rent from premises $12,000

Total opportunity cost $22,500

Revenue:

Revenues from Pizza $400,000

Revenue from Beverages $190,000

Total revenue $590,000

Expenses:

Cashier wages ($55,000 * 2) $110,000

Pizza ingredients $50,000

Manager salary $75,000

Pizza bakers wages ($60,000 * 3) $180,000

Equipment $10,000

Total Expense $425,000

Net Income - Accounting Profit ($590,000 - $425,000) = $165,000

Less opportunity cost $22,500

Economic Profit $142,500

4 0
2 years ago
A steam power plant operates on an ideal reheat- regenerative Rankine cycle and has a net power output of 80 MW. Steam enters th
trasher [3.6K]

Answer:

flow(m) = 54.45 kg/s

thermal efficiency u = 44.48%

Explanation:

Given:

- P_1 = P_8 = 10 KPa

- P_2 = P_3 = P_6 = P_7 = 800 KPa

- P_4 = P_5 = 10,000 KPa

- T_5 = 550 C

- T_7 = 500 C

- Power Output P = 80 MW

Find:

-  The mass flow rate of steam through the boiler

-  The thermal efficiency of the cycle.

Solution:

State 1:

P_1 = 10 KPa , saturated liquid

h_1 = 192 KJ/kg

v_1 = 0.00101 m^3 / kg

State 2:

P_2 = 800 KPa , constant volume process work done:

h_2 = h_1 + v_1 * ( P_2 - P_1)

h_2 = 192 + 0.00101*(790) = 192.80 KJ/kg

State 3:

P_3 = 800 KPa , saturated liquid

h_3 = 721 KJ/kg

v_3 = 0.00111 m^3 / kg

State 4:

P_4 = 10,000 KPa , constant volume process work done:

h_4 = h_3 + v_3 * ( P_4 - P_3)

h_4 = 721 + 0.00111*(9200) = 731.21 KJ/kg

State 5:

P_5 = 10,000 KPa , T_5 = 550 C

h_5 = 3500 KJ/kg

s_5 = 6.760 KJ/kgK

State 6:

P_6 = 800 KPa , s_5 = s_6 = 6.760 KJ/kgK

h_6 = 2810 KJ/kg

State 7:

P_7 = 800 KPa , T_7 = 500 C

h_7 = 3480 KJ/kg

s_7 = 7.870 KJ/kgK

State 8:

P_8 = 10 KPa , s_8 = s_7 = 7.870 KJ/kgK

h_8 = 2490 KJ/kg

- Fraction of steam y = flow(m_6 / m_3).

- Use energy balance of steam bleed and cold feed-water:

                                        E_6 + E_2 = E_3

               flow(m_6)*h_6 + flow(m_2)*h_3 = flow(m_3)*h_3

                                    y*h_6 + (1-y)*h_3 = h_3

                                  y*2810 + (1-y)*192.8 = 721

Compute y:                          y = 0.2018

- Heat produced by the boiler q_b:

                             q_b = h_5 - h_4 +(1-y)*(h_7 - h_8)

                    q_b = 3500 -731.21 + ( 1 - 0.2018)*(3480 - 2810)

Compute q_b:               q_b = 3303.58 KJ/ kg

-Heat dissipated by the condenser q_c:

                                       q_c = (1-y)*(h_8 - h_1)

                                 q_c= ( 1 + 0.2018)*(2810 - 192)

Compute q_c:               q_c = 1834.26 KJ/ kg

- Net power output w_net:

                                     w_net = q_b - q_c

                                w_net = 3303.58 - 1834.26

                                    w_net = 1469.32 KJ/kg

- Given out put P = 80,000 KW

                                     flow(m) = P / w_net

compute flow(m)          flow(m) = 80,000 /1469.32 = 54.45 kg/s

- Thermal efficiency u:

                                     u = 1 - (q_c / q_b)

                                     u = 1 - (1834.26/3303.58)

                                     u = 44.48 %

5 0
2 years ago
Outline an algorithm in **pseudo code** for checking whether an array H[1..n] is a heap and determine its time efficiency.
svlad2 [7]

Answer:

Condition to break: H[j] \geq max {H[2j] , H[2j+1]}

Efficiency: O(n).

Explanation:

Previous concepts

Heap algorithm is used to create all the possible permutations with K possible objects. Was created by B. R Heap in 1963.

Parental dominance condition represent a condition that is satisfied when the parent element is greater than his children.

Solution to the problem

We assume that we have an array H of size n for the algorithm.

It's important on this case analyze the parental dominance condition in order to the algorithm can work and construc a heap.

For this case we can set a counter j =1,2,... [n/2] (We just check until n/2 since in order to create a heap we need to satisfy minimum n/2 possible comparisionsand we need to check this:Break condition: [tex]H[j] \geq max {H[2j] , H[2j+1]}

And we just need to check on the array the last condition and if is not satisfied for any value of the counter j we need to stop the algorithm and the array would not a heap. Otherwise if we satisfy the condition for each j =1,2,.....,[n/2]p then we will have a heap.

On this case this algorithm needs to compare 2*(n/2) times the values and the efficiency is given by O(n).

3 0
2 years ago
A 60-kg woman holds a 9-kg package as she stands within an elevator which briefly accelerates upward at a rate of g/4. Determine
Anuta_ua [19.1K]

Answer:

force R = 846.11 N

lifting force L = 110.36 N

if cable fail complete both R and L will be zero

Explanation:

given data

mass woman mw = 60 kg

mass package mp = 9 kg

accelerates rate a = g/4

to find out

force R and lifting force L and if cable fail than what values would R and L acquire

solution

we calculate here first reaction R force

we know elevator which accelerates upward

so now by direction of motion , balance the force that is express as

R - ( mw + mp ) × g = ( mw + mp ) × a

here put all these value and a = g/4 and use g = 9.81 m/s²

R - ( 60 + 9 ) × 9.81 = ( 60 + 9  ) × g/4

R = ( 69  ) × 9.81/4  + ( 69 ) 9.81

R = 69  ( 9.81 + 2.4525 )

force R = 846.11 N

and

lifting force is express as here

lifting force = mp ( g + a)

put here value

lifting force = 9 ( 9.81 + 9.81/4)

lifting force L = 110.36 N

and

we know if cable completely fail than body move free fall and experience no force

so both R and L will be zero

5 0
2 years ago
Other questions:
  • Determine the amount of gamma and alpha phases in a 10-kg, 1060 steel casting as it is being cooled to the following temperature
    6·1 answer
  • The wall of drying oven is constructed by sandwiching insulation material of thermal conductivity k = 0.05 W/m°K between thin me
    8·1 answer
  • A circular ceramic plate that can be modeled as a blackbody is being heated by an electrical heater. The plate is 30 cm in diame
    15·1 answer
  • A subway car leaves station A; it gains speed at the rate of 4 ft/s^2 for of until it has reached and then at the rate 6 then th
    8·1 answer
  • Sea water with a density of 1025 kg/m3 flows steadily through a pump at 0.21 m3 /s. The pump inlet is 0.25 m in diameter. At the
    8·1 answer
  • The Gill Art Gallery wishes to maintain data on their customers, artists and paintings. They may have several paintings by each
    7·1 answer
  • The in situ moist unit weight of a soil is 17.3 kN/m3 and the moisture content is 16%. The specific gravity of soil solids is 2.
    12·1 answer
  • A thin-walled tube with a diameter of 6 mm and length of 20 m is used to carry exhaust gas from a smoke stack to the laboratory
    7·1 answer
  • The rigid beam is supported by a pin at C and an A992 steel guy wire AB of length 6 ft. If the wire has a diameter of 0.2 in., d
    14·1 answer
  • Dalton needs to prepare a close-out report for his project. Which part of the close-out report would describe
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!