3Rd Class Power Engineering A1 Chapter 6

The internal resistance to an external force applied to a body is known as:Incorrect Response 1) Young's modulus 2) Strain 3) Ultimate strengthCorrect Answer 4) Stress 5) Allowable strength

The ratio of a stress to the corresponding strain is known as:Correct Response 1) The modulus of elasticity 2) The ultimate strength 3) The maximum load 4) The yield point 5) Hooke's Law

When considering a steel block subjected to a tensile force, we would find the stress in the block by:Incorrect Response 1) Using the formula stress equals force divided by the area and using the same formula we use to find stress in a block subjected to a compressive forceCorrect Answer 2) Using the formula stress equals force divided by the area and using the same formula we use to find stress in a block subjected to a compressive force and using the same formula we use to find the shear stress in a bolt 3) Using the same formula we use to find stress in a block subjected to a compressive force and using the same formula we use to find the shear stress in a bolt 4) Using the formula stress equals force divided by the area and using the same formula we use to find the shear stress in a bolt 5) Using the same formula, we use to find the shear stress in a bolt.

Ultimate strength of a material is expressed in units of:Incorrect Response 1) KiloNewtons 2) KilowattsCorrect Answer 3) Kilopascals 4) Square metres 5) Joules

A steam engine has a piston 20 cm in diameter and a piston rod of 4 cm in diameter. If the ultimate strength for the rod material is 400 000 kPa and the factor of safety for the rod is 12, calculate the maximum allowable steam pressure. 1) 1.333 GPaCorrect Answer 2) 1 337.5 kPa 3) 3 333 kPa 4) 192 000 kPa 5) 6 031.87 kPa

The bending moment at any section in a beam is the algebraic sum of:Incorrect Response 1) The upward forces and downward forces 2) The distributed loads and the concentrated loads 3) All the force couples acting on the beamCorrect Answer 4) Moments to the left or the right of the section being considered 5) Moments at the support

A perfectly elastic material: 1) Will take any shape due to elastic ability 2) Can only be loaded to the yield pointIncorrect Response 3) Can only loaded to the elastic limitCorrect Answer 4) Shows no sign of strain due to loading when the load is removed 5) Maintains a new length or shape after the load is removed

Strain is defined as: 1) Original length multiplied by the change in lengthCorrect Answer 2) Deformation per unit lengthIncorrect Response 3) Original length divided by the change in length 4) Original length divided by the change in area 5) Force which causes a change in body shape

When calculating the ultimate strength of a material, we should:Correct Answer 1) Divide the maximum load by the original cross-sectional area 2) Divide the maximum load by the new cross-sectional area 3) Multiply the maximum load by the new cross-sectional area 4) Multiply the maximum load by the original cross-sectional areaIncorrect Response 5) Multiply the maximum load by the original cross-sectional area

Hooke's Law determines the constant proportionality of:Correct Response 1) Stress to strain relation of a body 2) Area to load on a body 3) Unit stress of a body 4) Unit strain of a body 5) Change in length to original length of a body

A cantilever pivoted at one end is 6 m long. The load, due to the lever's weight, is 9 N and acts through the midpoint. At 1 m from the pivoted end, a force of 298 N acts in an upward direction. To keep the system in balance, a load must be placed at the extreme end of the cantilever. What is the magnitude of that load?

1) 149.79 N

2) 45.17 kg

3) 41.75 kg

4) 244 N

5) 45.17 N

The yield point of a material is where:Correct Response 1) The breaking point of the specimen occurs 2) The maximum load is applied 3) The material can be returned to the original size and shape 4) The material suddenly yields to the load 5) The factor of safety is increased suddenly

When conducting an ultimate tensile strength test, the cross-sectional area of the specimen used for calculation is: 1) The area after the test is conducted 2) Always the area taken at 100°CIncorrect Response 3) The area during the testCorrect Answer 4) The area before the test is conducted 5) The area between the elastic limit and yield point