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EDEXCEL NATIONALS

UNIT 6 MECHANICAL PRINCIPLES and APPLICATIONS

ASSIGNMENT No. 4

NAME:

I agree to the assessment as contained in this assignment. I confirm that the work submitted is my own work.

Signature Date submitted

Learning outcomes

On completion of this unit a learner should:

1 Be able to determine the effects of loading in static engineering systems

2 Be able to determine work, power and energy transfer in dynamic engineering systems

3 Be able to determine the parameters of fluid systems

4 Be able to determine the effects of energy transfer in thermodynamic systems.

FEEDBACK COMMENTS

This assignment only assesses P7, P8, P9, M3 and M4.

Grade Awarded:

Assessor Signature__________________________________ Date:____________________

Internal verifier Signature_____________________________ Date:____________________

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Grading gridIn order to pass this unit, the evidence that the learner presents for assessment needs to demonstrate that they can meet

all of the learning outcomes for the unit. The criteria for a pass grade describe the level of achievement required to passthis unit.

Grading criteria

To achieve a pass grade the evidence

must show that the learner is able to:

Achieved To achieve a merit grade the

evidence must show that, in

addition to the pass criteria,

the learner is able to:

Achieved To achieve a distinction

grade the evidence must

show that, in addition to the

pass and merit criteria, thelearner is able to:

Achieved

P1 calculate the magnitude, direction

and position of the line of action

of the resultant and equilibrant

of a non-concurrent coplanar

force system containing a

minimum of four forces acting

in different directions.

M1 calculate the factor of

safety in operation for a

component subjected to

combined direct and

shear loading against

given failure criteria.

D1 compare and contrast

the use of

DAlemberts principle

with the principle of

conservation of energy

to solve an engineering

problem.

P2 calculate the support reactions of a

simply supported beam carrying

at least two concentrated loads

and a uniformly distributed load

M2 determine the retarding

force on a freely falling

body when it impacts

upon a stationary

object and is brought to

rest without rebound,

in a given distance.

D2 evaluate the methods

that might be used to

determine the density

of a solid material and

the density of a liquid.

P3 calculate the induced direct stress,

strain and dimensional change

in a component subjected to

direct uniaxial loading and the

shear stress and strain in a

component subjected to shear

loading.

M3 determine the thermal

efficiency of a heat

transfer process from

given values of flow

rate, temperature

change and input

power.

P4 solve three or more problems that

require the application of kinetic

and dynamic principles to

determine unknown system

parameters.

M4 determine the force

induced in a rigidly

held component that

undergoes a change in

temperature.

P5 calculate the resultant thrust and

overturning moment on avertical rectangular retaining

surface with one edge in the free

surface of a liquid.

P6 determine the up-thrust on an

immersed body.

P7 use the continuity of volume and

mass flow for an incompressible

fluid to determine the design

characteristics of a gradually

tapering pipe.

P8 calculate dimensional change when

a solid material undergoes a

change in temperature and theheat transfer that accompanies a

change of temperature and

phase.

P9 solve two or more problems that

require application of

thermodynamic process

equations for a perfect gas to

determine unknown parameters

of the problems.

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ASSIGNMENT DETAILS

The diagram shows two tanks of liquid. Tank 1 is heated by hot gas passing through a heating coil

as shown. When the liquid is at the right temperature, a tap is opened and the hot liquid passes

along to tank 2 through an insulated pipe.

PART 1

At a given moment in time, the flow rate is 5 kg/s. Calculate the following.

1. The velocity of liquid flowing in the pipe.

2. The velocity of the surface of tank 1 as it falls.

3.

The velocity of the surface of tank 2 as it rises.

DATA

Tank 1 has a cross sectional area of 6 m2.

Tank 2 has a cross sectional area of 4 m2.

The pipe has a bore of 80 mm.

The liquid has a density of 920 kg/m3.

PART 2

The liquid in tank 1 is heated up and released into the pipe. Calculate the following.

1. The change in length of the pipe if it is free to expand.

2. The stress and strain in the pipe if it is not free to expand.

DATA

The pipe length is 5 m.

The modulus of elasticity for the pipe is 200 GPa

The coefficient of linear expansion for the pipe is 15 x 10 -6K-1

The temperature of pipe before the liquid is released is 20oC

The temperature of pipe after the liquid is released is 160oC

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PART 3

The liquid in tank 1 is heated from 20oC to 160oC in 40 minutes. Calculate the following.

1. The heat transfer

2. The average rate of heat transfer.

DATA

The specific heat capacity of the liquid is 1970 J/kg K.

The mass heated up in the tank is 400 kg.

PART 4

The heating coil uses hot gas that becomes cooled as it passes through the coil. Calculate the

following.

1. The volume of hot gas flowing at inlet.

2. The velocity of the gas at entrance.

3. The volume of the cool gas at exit.

4. The velocity of the cool gas at exit.

DATA

The inlet temperature of the gas is 500oC.

The absolute inlet pressure is 5 bar (500 kPa).

The exit temperature of the gas is 110oC.

The absolute pressure at exit is 1.2 bat (120 kPa)

The mass flow rate of the gas is 0.15 kg/s.

The characteristic gas constant is 190 J/kg K

The bore of the coil is 50 mm.

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STUDENT and TUTOR GUIDE TO DOING THIS ASSIGNMENT

If you are unable to get started or make progress you should seek assistance from your tutor and

your grades will be determined by how much assistance you need.

Tutors may purchase the full solution from admin@www.freestudy.co.uk.

This also includes a Mathcad file for solving variations of the problem by changing the data. Thiswill enable tutors to set different assignments and so reduce the risk of copying.

TO OBTAIN A DISTINCTION

You should do all parts correctly with the minimum of assistance. Your solutions should be

exceptionally clear and accurate and the symbols used should be clearly indicated in the formula

you create to evaluate your answers. Your answers should be checked for accuracy by for example,

calculating the original data from your answers to see that it is the same. You should show clearly

all the principles involved in the solution and state who they are attributed to. You should make

correct use of units and multiples.

TO OBTAIN A MERIT

You should do all parts with only minor errors. You should not require more than basic assistance

to complete the assignment. You should draw clear diagrams illustrating the principles used to

arrive at your solutions. You should make correct use of units and multiples.

TO OBTAIN A PASS

You should attempt all parts and demonstrate that you understand the principles involved to solve

the answers. You will probably have asked for help in drawing a free body diagram and in resolving

the forces appropriately. You should demonstrate that your calculations are accurate and use the

correct units and multiples.

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