Exam 2013, answers PDF

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Examination Answers – Semester 1, 2013 PHYC10001 Physics 1: Advanced These are answers to the exam questions, not complete solutions. Answers provided to questions requiring explanations do not represent complete solutions, and would in most cases not receive the full marks allocated on the exam paper. Many marks are given on the exam for ‘working’ (i.e. for showing that you understand the relevant physics), and a numerical answer alone is usually not sufficient to gain full marks. 1. (a)

m/s.

m/s;

(b)

Assuming that the net external force acting on the cars during the collision is negligible, momentum is conserved. km/h.

(c)

Inelastic. (Total kinetic energy of the two cars is not conserved in the collision.)

(a)

Diagram should show the weight force acting vertically downwards, and two normal forces: one perpendicular to the sloping surface of the wheel and the other perpendicular to the (vertical) rim of the wheel. There may also be friction forces directed out of the page (opposite to the direction of motion of the ball).

2.

(b)

m/s.

(c)

s.

3. (a) (i) (ii) (b)

.

Kepler III:

(c) (d)

m/s.

h. Proof required.

(e) (i) (ii)

Exam Answers 2013

. mm.

PHYC10001 Physics 1: Advanced

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4. (a)

.

(b)

.

(c)

(d)

J.

(e)

.

(f)

Ratio:

(a)

Propagation speed and wavelength both change. Frequency and period do not change. Explanations required.

5.

(b) (i) (ii) (iii) (iv) (v) (vi)

. N/m. m/s. m. 28 m. 5.0 oscillations.

6. (a)

.

(b) (i) (ii)

m. (1) (2)

. m.

(c) (i) (ii)

Proof required. . .

(iii) 7. (a) (i) (ii) (iii) (iv)

Exam Answers 2013

J. . ly = yr =

au. s = minutes.

PHYC10001 Physics 1: Advanced

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(b) (i) (ii) (iii) (iv) (v)

Exam Answers 2013

Proof required. is not a proper time interval because in the frame of reference events 1 and 2 do not occur at the same place (same ). . Use the results from parts (i) and (iii) to work out , then convert to an expression involving frequencies. Professor X is mostly incorrect, though he does make a few valid points. As we saw in part (iv), to derive the relativistic Doppler formula, we have to consider the relative motion of source and receiver as well as the time dilation of the source frequency that is observed by the detector. According to the detector, the source clock runs slow, but this has nothing to do with the travel time of the light from source to detector.

PHYC10001 Physics 1: Advanced

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