Mid-Year Examination Part 1

Physics – Part 1

PHYSICS

Subject Code: PHY415114

Mid-year Examination – Part 1

2016

Time: 50 minutes

On the basis of your performance in this examination, the examiners will provide results on each of the following criteria taken from the syllabus statement:

Criterion 5 Demonstrate knowledge and understanding of Newtonian Laws

including gravitational fields.

Name: / Teacher:
Criterion / Mark
5 / /45

CANDIDATE INSTRUCTIONS

You MUST ensure that you have addressed the externally assessed criterion on this examination paper.

Answer ALL questions. Answers must be written in the spaces provided on the examination paper.

The 2016 Physics Information Sheet can be used throughout the examination.

Show all workings in your answers to numerical questions. Some credit will be given for simplified answers but no credit will be given for an incorrect answer, unless it is accompanied by details of the working. Appropriate units must be included.

All written responses must be in English.

Question 1

A cricket ball is hit at the Big Bash at the MCG in Melbourne. The boundary is 75m from the batsman who hits it at a height of 1.5m above the cricket pitch.

The ball is hit at 400 to the horizon at a speed of 27 ms-1.

(a)What are the horizontal and vertical components of the initial velocity? (2 marks)

…………………………………………………………………………………………………

(b)What is the final vertical velocity of the ball on hitting the ground? (3 marks)

…………………………………………………………………………………………………

(c)What distance horizontally does the ball travel? (2 marks)

…………………………………………………………………………………………………

(d)Predict whether a fielder with a reach of 2.5m could catch the ball at the boundary of 75m?

(2 marks)

…………………………………………………………………………………………………

Question 2

An engineer designed a road that had a horizontal curved section of radius(50 ± 5) m.

After construction, it was necessary to check that the curvature of the road was within tolerance.

To test the curvature of the road, the engineer hung a small mass of 100g from the rear-view mirror of his car using a light string. He then travelled at a constant speed of 35.0 km/h aroundthe curve. The engineer observed that the string holding the mass settled at an angle of 10.0° to thevertical.

(a) On the diagram above, draw and label the forces acting on the hanging object.

(2 marks)

(b) Calculate the tension in the light string. Show all workings.

(2 marks)

…………………………………………………………………………………………………

(1 mark)

…………………………………………………………………………………………………

(d) From the information supplied and your previous answers, determine whether the curvature of the road was correct. Show all workings.

(2 marks)

…………………………………………………………………………………………………

Question 3

A ball of mass 1.5 kg rolls from point A, along a rail that includes a vertical loop of radius (R) 0.9 m as shown. There is negligible friction.

(i) What is the minimum speed that the ball must maintain to maintain contact at all times in the loop?

(2 marks)

…………………………………………………………………………………………………

(ii) On the diagram above, draw and label the forces acting on the ball when it is at point A.

(2 marks)

(iii) If the release point of the ball rail is from an incline of 180, what is the minimum distance up the ramp that the ball can be released from to maintain contact at all times in the loop?

(2 marks)

…………………………………………………………………………………………………

Question 4

A bob sled team conducts a trial for the winter Olympics. After a run-up pushing the sled they pass the starting point. At different time intervals the sled’s speed is recorded.

Time (s) / 2 / 5 / 6 / 10 / 16 / 20
Velocity (m/s) / 14 / 28 / 30 / 46 / 66 / 83

(i)What equation best describes the physics of the situation?

(2 marks)

…………………………………………………………………………………………………

(ii)Use the data to draw a velocity~time graph.

(4 marks)

(iii)Use your graph to find the initial speed of the sled as it passes the starting point.

(1 marks)

…………………………………………………………………………………………………

(iv)Use the information from your graph to determine the angle of the slope of the ground which is accelerating the sled.

(2 marks)

…………………………………………………………………………………………………

Question 5

An exoplanet is a planet that revolves around a star that is not our Sun. One such exoplanet revolves around a distant star and it causes the star to oscillate, or wobble.

(a)Explain why the star has been observed to oscillate or ‘wobble’?

(2 marks)

…………………………………………………………………………………………………

In the following calculations, assume that the centre of the exoplanet’s orbit coincides with the star’s centre of mass, and that the orbit is circular.

Some details of the star and the exoplanet are shown below:

Mass of the star: kg

Mass of the exoplanet: kg

Orbital radius of the exoplanet: m

(b)Show that the magnitude of the gravitational force acting on the exoplanet is

…………………………………………………………………………………………………

(2 marks)

(c)Calculate the exoplanet’s orbital velocity.

…………………………………………………………………………………………………

(3 marks)

(d)Calculate the exoplanet’s orbital period, and express your answer in hours.

…………………………………………………………………………………………………

(3 marks)

Question 6

A group of NASA scientists were calculating the escape velocity of a 4800 kg rocket.

(i) If it is sitting on a launching pad on the equator, what is the potential energy of the rocket?

(2 marks)

…………………………………………………………………………………………………

(ii)What is the kinetic energy of the rocket?

(1 mark)

…………………………………………………………………………………………………

(iii)Show that the escape energy of the rocket from the Earth is about 3 x 1011 J?

(1 mark)

…………………………………………………………………………………………………

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