Written Assignment

QUESTION 1 - Sketch the part below in a 3rd angle projection. Ahandsfree sketch is acceptable or you can use software if you have access to it. Please insert your sketch as an image underneath this question.  

QUESTION 2 - Sketch the part below in an isometric projection. Ahandsfree sketch is acceptable or you can use software if you have access to it. Please insert your sketch as an image underneath this question.

QUESTION 3 - Differentiate between static and kinetic friction.

QUESTION 4 - An object of mass 10 kgs encounters a frictional force when sliding to the right.  Given the coefficient of friction between the object and the surface is 0.15, Determine:

a) The normal force

b) The gravitational force

c) The frictional force

QUESTION 5 - Name three reasons why limits and fits are used in mechanical systems.

QUESTION 6 - a. Differentiate between unilateral and bilateral tolerance.

b. Describe the condition under which maximum clearance fit is obtained.          

QUESTION 7 - Describe the conditions under which tensile, compressive and shear strains occur.

QUESTION 8 - Critical Question

Note - This Critical question is mandatory. It should be answered and students are expected to get this question completely right to be assessed as competent with a score for this module.

A hollow circular aluminum tube of 1 m length and inside and outside diameters of 90mm and 120mm respectively supports a compressive load of 240 kN. If the tube shortens by 0.5 mm, determine the compressive stress and strain.     

QUESTION 9 - Sketch the stress-strain diagram for a typical steel, and then list/explain the important parts of the graph.  Ahandsfree sketch is acceptable or you can use software if you have access to it. Please insert your sketch as an image underneath this question.

QUESTION 10 - What is the difference between ferrous and non-ferrous metal alloys and give two typical applications for each?

QUESTION 11 - Explain in simple terms, the difference between the hardness & toughness properties of a material.

QUESTION 12 - When examining a fracture, how would we distinguish between ductile and brittle failures?

QUESTION 13 - a) Explain the process of creep as applied to metals.

b) Give one example of a component/equipment that is subject to creep failure.

QUESTION 14 - Explain why we need a factor of safety in design?

QUESTION 15 - An object is accelerating at 4m/s2. If the mass is halved and the net force tripled;

a) What will be the new acceleration? And,

b) Determine the acceleration if the mass of the object is doubled, with all other conditions remaining the same.

Establish a relationship between Acceleration, Mass and Force then determine what happens to the acceleration in that relationship when 1) the Mass and Force are changed and 2) the mass is changed but the force remains the same.

QUESTION 16 - Is the yield point well defined in the case of brittle materials? Define factor of safety for brittle materials.

QUESTION 17 - Determine the tensile stress in the bolted connection shown below for the load F = 210 kN. Using a safety factor of 2, determine whether the plates will fail or not if the yield strength of the plate material is 270 MPa and the thickness of the plate is 12 mm. The nominal diameter of the bolts is 10 mm and the clearance holes in the plate are drilled 10.5mm diameter.

QUESTION 18 - Define fatigue failure? What are its characteristics?

QUESTION 19 - Which are the three equations of static equilibrium?

QUESTION 20 - Critical Question

Forces of magnitude 6N, 9N and 5N are applied to a rod AB of length 10m, as shown below. Calculate the sum of the moments about the midpoint of the rod.

QUESTION 21 - a. Why are washers used with fasteners?

b. Which is the preferred key type used on tapered shafts and explain the reason for it?

QUESTION 22 - What causes shear failure and member tear in riveted joints?

QUESTION 23 - Why do we harden steel? Explain what process you can use if there is insufficient carbon in the steel.

QUESTION 24 - What is the difference between Tempering and Annealing?

QUESTION 25 - Explain the main difference between hot working and Cold working of metals.

QUESTION 26 - a. For which type of components is forging generally employed?

b. List some of the significant advantages associated with extrusion.

QUESTION 27 - Define pressing. Name one important application where it is used and explain why.

QUESTION 28 - Explain the difference between Direct Numerical Control and Distributed Numerical Control and show it by means of simple block diagrams.

QUESTION 29 - What is meant by CNC?

QUESTION 30 - Define rapid prototyping. Give some examples of its application areas.

QUESTION 31 - What are the advantages of using rapid prototyping techniques?

QUESTION 32 - What process would you use to manufacture the parts shown below?

QUESTION 33 - a. How can the up down movement of the drilling tool in a drill press be controlled?

b. What purpose do coolants serve in lathe operation?

QUESTION 34 - What is the principle involved in broaching operation?

QUESTION 35 - How is machining carried out in a shaper? List some of the shaper applications that are undertaken using special tools.