##### a=2 b=1 A bullet is to be tested in the laboratory to determine the drag force...

a=2 b=1

A bullet is to be tested in the laboratory to determine the drag force on it. Dependent parameter the drag force D (Newton) depends on the velocity of the bullet V(m/s), the length of the bullet L(m), sound velocity c(m/s), density of fluid ρ (kg/m3) and dynamic viscosity µ(kg/ms).

Solve the problem by making the necessary assumptions and drawing the schematic figure

I-Determine the nondimensional p parameters using repeating variables

ii-a bullet with a speed of 9a,b m/s in air may be modelled in a water tunnel with a test section velocity of 2ab cm/s. Determine the length of the model, if the length of the bullet is 5a,b mm. The air and water temperature is 20 oC degree at 1 atm.

iii- if the drag force on the model is measured to be 2,ab N, then determine the expected drag force on the bullet. Comment on dynamic similarity equivalence?

In: Mechanical Engineering

##### The compression ratio of an ideal air-powered Diesel cycle is 20. At the beginning of the...

The compression ratio of an ideal air-powered Diesel cycle is 20. At the beginning of the compression process, the pressure of the air is 100 kPa, the temperature is 20 ° C, and the highest temperature of the cycle is required not to exceed 2250 K. Show the cycle in the P-v diagram. Accept specific temperatures constant at room temperature.

k=1.4 CP=1.005 kJ/kgK CV=0.718 kJ/kgK R=0.287 kJ/kgK

a) Calculate the temperatures entering and leaving the cycle, the thermal efficiency of the cycle,

b) Calculate the average effective pressure of the cycle.

In: Mechanical Engineering

##### Vibration absorbers are used in railroad cars to protect sensitive loads from large acceleration due to...

Vibration absorbers are used in railroad cars to protect sensitive loads from large acceleration due to periodic excitation given by rail links. For certain trains, the rail connection is 5 m. The car, when empty, has a mass of 25,000 kg. Two vibration absorbers are used, each having a mass of 12,000 kg. Absorbers for certain cars are designed to remove vibrations from the main mass when the car is loaded with 12,000 kg of cargo and moves at 100 m / s. The personal frequency of the uncarried carriage is 165 rad / s.

(a) At what speed will resonance occur in cars with a load of 12,000 kg?

(b) What is the best speed for carriages when loaded with 25,000 kg of cargo?

In: Mechanical Engineering

##### You are invited to give a talk to SPM students who wish to choose their future...

You are invited to give a talk to SPM students who wish to choose their future career in engineering field. As a young engineer graduated from UPNM, you are being selected to give a short introductory speech on the profession of Mechanical Engineer to the students. Write a short outline of the speech which should cover the following topics; explanation of engineering, mechanical engineering, profession, professionalism, attributes and their roles to the society.

In: Mechanical Engineering

##### A 6.2-mm-diameter electrical transmission line is exposed to windy air. Determine the drag force exerted on...

A 6.2-mm-diameter electrical transmission line is exposed to windy air. Determine the drag force exerted on a 165-m-long section of the wire during a windy day when the air is at 1 atm and 15°C and the wind is blowing across the transmission line at 65 km/h.

The density and kinematic viscosity of air at 1 atm and 15°C are ρ = 1.225 kg/m3 and ν = 1.470×10-5 m2/s.

_____ N

In: Mechanical Engineering

##### Course : Heat Transfer question 3 a-) In heat transfer by radiation, describe the swallowing,reflection, passing...

Course : Heat Transfer

question 3

a-) In heat transfer by radiation, describe the swallowing,reflection, passing coefficients, write down the relation between them.

b-)Write the expression radiative heat transfer between two surfaces with different areas in a closed volume.

In: Mechanical Engineering

##### Show that 2D potential flows satisfy Euler’s equations even if μ ≠ 0.

Show that 2D potential flows satisfy Euler’s equations even if μ ≠ 0.

In: Mechanical Engineering

##### Question 1) Water at 20 C flows through a galvanized pipe at an average speed of...

Question 1) Water at 20 C flows through a galvanized pipe at an average speed of 2.5 m / s. The diameter of the pipe is 150 mm. The roughness of the pipe surface is 60 μm. Calculate the pressure drop in this pipe since the total length of the pipe is 300 meters. Take the necessary values for calculations from tables and diagrams.

In: Mechanical Engineering

##### 1. Mention fundamental differences from the Auto Pilot system, Stability Augmentation System, and Command Augmentation System?...

1. Mention fundamental differences from the Auto Pilot system, Stability Augmentation System, and Command Augmentation System?

2. State the fundamental differences between the Hydro-mechanical Assisted Control System and the Hydro-mechanical Powered Control System?

In: Mechanical Engineering

##### 1) Give 3 methods to determine machining time. 2) What is the difference between process optimisation...

1) Give 3 methods to determine machining time.

2) What is the difference between process optimisation and economic.

3) From your understanding, would the costing calculation make difference from one machining process to another.Why?

In: Mechanical Engineering

##### 1.Why is the hole missing ? •Operator error. 2.Why did the operator make the error ?...

1.Why is the hole missing ?
•Operator error.

2.Why did the operator make the error ?
•He wasn’t inspecting the parts as required.

3.Why wasn’t he inspecting the parts ?
•The supervisor told him we are behind in the shipping schedule.

4.Why are we behind in the shipping schedule ?
•The raw material was late in arriving.

5.Why was the raw material late in arriving ?•The supplier underestimated the lead time.

In: Mechanical Engineering

##### 1.Why is the hole missing ? •Operator error. 2.Why did the operator make the error ?...

1.Why is the hole missing ?
•Operator error.

2.Why did the operator make the error ?
•He wasn’t inspecting the parts as required.

3.Why wasn’t he inspecting the parts ?
•The supervisor told him we are behind in the shipping schedule.

4.Why are we behind in the shipping schedule ?
•The raw material was late in arriving.

5.Why was the raw material late in arriving ?•The supplier underestimated the lead time.

In: Mechanical Engineering

##### A steel drill rod that is 10 mm in diameter and 20 cm long is being...

A steel drill rod that is 10 mm in diameter and 20 cm long is being heat treated in an oil bath. The 1050°C rod is quenched and held at 700°C and then quenched a second time to 30°C. Calculate the quantities of heat that must be removed at the two quenching stages. Weight density of steel as ρw = 76 kN/m3 , The specific heat of steel is c= 0.50 kJ/(kg . ºC).

In: Mechanical Engineering

##### Combustion gases with an average specific heat ratio of k=1.33 and a gas constant of R=0.280...

Combustion gases with an average specific heat ratio of k=1.33 and a gas constant of R=0.280 kJ/kgK enter a 10-cm-diameter adiabatic duct with inlet conditions of Ma1=2,21 T1=521 K, and P1 =182,1 kPa. If a normal shock occurs at a location 2021 mm from the inlet, determine the velocity, temperature, and pressure at the duct exit. Take the average friction factor of the duct to be 0.01021. Calculate the static stagnation pressure, temperature and density values of the flow at the duct outlet.

Solve the problem by making the necessary assumptions and drawing the schematic figure.

In: Mechanical Engineering

##### A mass of 0.07 kg of air at a temperature of 30°C and pressure 100 kPa...

A mass of 0.07 kg of air at a temperature of 30°C and pressure 100 kPa is compressed to a pressure of 600 kPa, according to the law:

(i.e. Polytropic process, n=1.3). Determine:

i.The final volume

ii.The final temperature

iii.The work transfer

iv.The change in internal energy

v.The heat transfer

In: Mechanical Engineering