Ep Exam Stuff > Engp_exam Qs_03

UNIVERSITY OF SOUTH AUSTRALIA Applied Physics - School of Electrical & Information Engineering ENGINEERING PHYSICS

[1] Find in your pigeon hole changes to the formulae from last years paper which I assume you are modifying. [2] Please add the following to the formulae section: TRIGONOMETRIC RELATIONS a.b = ab cos θ In any triangle a2 = b2 + c2 − 2bc cos α C = 2π r A = π r2 UNCERTAINTY RELATIONS When y = axn : ∆y/y = n ∆x/x When y = ax.z or y = ax/z : ∆y/y = ∆x/x + ∆z/z

[3] My 7 multiple choice questions 15. Which statement is true about the unit vectors i, j and k? A. B. C. D.

j x i = k, i x i is meaningless, i x j = j x i, If i is directed west and j is directed perpendicular out from the earths surface, k points north.

16. An aircraft comes in for a crash landing as it can not lower the landing gear. As it slides along the tarmac on it’s undercarriage, which force does the most work? A. the normal force, B. the frictional force, C. neither A or B do any work, D. either A or B depending on the value of the kinetic coefficient of friction, µk.

17, 18, 19 Keep #17, 18 & 19 from last year

20. In mechanical equilibrium, an object must have, A. B. C. D.

constant acceleration, no forces acting on it, no translational or rotational acceleration, none of the above.

21. What is the buoyancy force of a fluid upon an object that sinks in the fluid? A. B. C. D.

zero, an upward force equal in magnitude to that of the weight of the object, an upward force equal in magnitude to the magnitude of the weight of a quantity of fluid equal to the objects volume. an upward force equal to gravity times the difference in density of the fluid and the object.

If you are making one paper, then I assume it will be much like the Applied Physics 1 paper. Last year I had 30 mins total for the Qs & Problems so I will assume 10 mins for Qs and 20 mins for Problems. In order to cover some of the syllabus I would have to support some form of choice so …?, I will give them a choice, 2 out of 3 Qs and 2 out of 3 problems. However, if mixed with you and John they may not do any of our section??? Maybe its best like ApplPhys1, give them choice in the Qs and they must do the problems.

[4] Two Questions Q5.

EITHER (a)

What kind of deformation does a cube of jelly exhibit when it ‘jiggles’? Explain, and define the appropriate elastic modulus.

OR (a) Quote and explain, with the aid of an appropriately labelled diagram, Bernoulli’s equation for fluid flow. Give an explanation of the physical significance of each term, and group of terms, in the equation. ……………………………………………………………………………………………………………… ……………………………………………………………………………………………………………… ……………………………………………………………………………………………………………… ……………………………………………………………………………………………………………… Q6.

EITHER (a)

Identify and briefly describe ALL the forces acting on a person sliding across a horizontal surface. Also identify and briefly describe the ‘reaction’ force corresponding to each force. Use diagrams as appropriate.

OR (b)

What do we mean when we say that “the unit vectors i, j and k form a right handed coordinate system”. If we take any two vectors A and B, then describe what we mean by the cross product of two vectors i.e. AxB=C and the dot product of two vectors i.e. A.B=C. Draw a diagram to aid your explanation.

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[5] Three Problems 7.

(i) While exploring a cave, a spelunker starts at the entrance and moves the following distances: She goes 75.0 m North, 250 m East, 125 m at an angle 30.0o North of East. Find the resultant displacement from the cave entrance. (ii) If man is to live in space then artificial gravity has to be generated to avoid atrophy of the muscles and weakening of the bones. It is proposed to spin a donut shaped space station to produce an artificial gravity of 1g. If the station has a diameter of 400.0 m then determine the rotation rate required.

8.

(i) The most common isotope of radon is 222Rn which has a half life of 3.82 days. What fraction of the nuclei that existed one week ago still remains? (ii) Sports medicine testing showed that the head of Greg Normans golf club (mass 0.200 kg) was traveling at 60.00 m/s just before it struck the 46.0 g golf ball which was at rest on the tee. Immediately after the collision the club head was traveling in the same direction at 40.00 m/s. Find the speed of the golf ball just after impact.

9.

Use Problem 15 from last years paper.

PROBLEMS ( 9 MARKS ) Question 1 (3 marks) Compare a small raindrop and a large raindrop falling through the atmosphere. Compare their terminal speeds. What are their accelerations when they reach terminal speed? ………………………………………..…………………………………………………………………………… ………………………………………..…………………………………………………………………………… ………………………………………..…………………………………………………………………………… ………………………………………..…………………………………………………………………………… ………………………………………..…………………………………………………………………………… ………………………………………..…………………………………………………………………………… ………………………………………..…………………………………………………………………………… ………………………………………..……………………………………………………………………………

Problem 1 (4 marks) An archer pulls her bow string back 0.4 m by exerting a force that increases uniformly from zero to 230 N. (i) What is the equivalent spring constant of the bow? ………………………………………………..………………………………………………………………………… … ………………………………………………..………………………………………………………………………… … ………………………………………………..………………………………………………………………………… … ………………………………………………..………………………………………………………………………… … ………………………………………………..………………………………………………………………………… … ………………………………………………..………………………………………………………………………… … (ii) How much work is done in pulling the bow string back? ………………………………………………..………………………………………………………………………… … ………………………………………………..………………………………………………………………………… … ………………………………………………..………………………………………………………………………… … ………………………………………………..………………………………………………………………………… … ………………………………………………..………………………………………………………………………… … ………………………………………………..………………………………………………………………………… … Problem 2 (2 marks) A 6 kg bowling ball moves at 3.00 m/s down a bowling lane. How fast must a 46 g golf ball move so that the two balls have the same kinetic energy?

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