Suggested time (40-45 minutes)
1 In physics the word gradient means....
a.... rigid.
b.... worthy.
c.... the area under a graph.
d.... the slope of a line.
2 Which of the following is a vector?
a Pressure
b Mass
c Heat
d Momentum
3 The force needed to bring the ball into equilibrium is....
4 The force that makes sticky tape sticky is called....
a ... cohesion.
b ... adhesion.c ... friction.
d.... viscosity.
5 A young man is hanging on a wall. His arms are perpendicular to the wall.
How many forces are acting on the man?
a. One
b.Two
c.Four
d.Five
6 A block is sliding across a uniform rough floor.
Which statement is correct?
a The acceleration of the block is constant.
b The energy of the block is constant.
c The momentum of the block is constant.
d The velocity of the block is constant.
7 Three masses of 2, 2, and 4 kg respectively, are equally spaced one meter apart in a straight line, smallest to largest. The center of mass is close to....
8 A flat plate is hanging and oscillating up and down on a steel spring.
The amplitude of the oscillation is decreasing mainly because....
a ... of air resistance.
b ... all oscillations die away.
c ... kinetic energy is conserved in all systems.
d ... energy is converted to heat in the steel spring.
9 A light bar has weights hanging as shown.
The bar is in equilibrium.
The sum of the moments about the point A is....
a.... 8 Nm
b.... 4 Nm
c.... 40 Nm
d.... zero
Questions 10 -12 refer to the velocity-time graph shown ...
... for a mass moving in a straight line under the influence of a single unbalanced force. The velocity is shown on the vertical axis in meters per second.
10 The distance traveled in the first 2 seconds was....
a.... 5 meters.
b....10 meters.
c.... 20 meters.
d.... 30 meters.
11 Refer to the velocity-time graph above.
The force on the mass is negative and not zero between....
a.... between zero and 2 s
b.... between 2 and 4 s.
c.... at 5 s.
d.... between 4 and 6 s.
12 Refer to the velocity-time graph above.
The mass will be farthest from the starting point....
a ... at five seconds.
b.... some time before six seconds.
c.... at six seconds.
d.... some time after six seconds.
13 A student is making graphs of a ball bouncing on a level floor. She has the motion detector above the ball and plots the velocity time graph shown.
The slope of the heavy straight line segments is close to....
a ... +10 m/s
b ... -10 m/s
c ... +10 m/s/s
d ... -10 m/s/s
14 Two cars are traveling in opposite directions. Acr A has a speed of 10 m/s and a mass of 2000 kg. Car B has a speed of 20 m/s and a mass of 1000 kg.
The total momentum is....
a....10000 kg m/s.
b.... 20000 kg m/s.
c.... 50000 kg m/s.
d.... zero.
15 A boy stands on a bridge 80 meters above a river. He drops a mass of 10 kg. It takes four seconds to reach the water.
The impulse applied to the mass by gravity as it falls all the way to the water is....
a.... 40 N s.
b.... 200 N s.
c ... 400 N s.
d.... 1000 N s.
16 The speed of the mass in question 15, just before it hits the water is....
a.... 40 m/s.
b.... 80 m/s.
c.... 100 m/s.
d.... 200 m/s.
17 Two equal masses are blown apart by a charge detonated between them.
The final relative speeds can be found by....
a ... knowing the momentum before and after the collision.
b ... knowing the kinetic energy after the collision.
c ... knowing the coefficient of restitution.
d ... none of these.
18 Two projectiles of the same mass are launched at different angles. They reach the same height.
Which statement is also true?
a They both had the same kinetic energy at launch.
b They both had the same momentum at launch.
c They will have have the same time of flight on level ground.
d They had have the same initial speed.
Questions 19 and 20 refer to the diagram of a block
sliding down a uniform rough slope [initially at constant speed].
19 Which statement is correct when the speed is constant?
a There is an unbalanced force acting down the plane
b The sum of the two forces acting on the block is zero.
c The sum of the three forces acting on the block is zero.
d The sum of the four forces acting on the block is zero.
.
20 The same block now begins to accelerate.
If the angle of the slope is unchanged which statement is true?
a The weight of the block has increased.
b The friction force has reduced.
c The force due to gravity has increased.
d The normal force has changed direction.
21 The refractive index of any transparent uniform material is given by the ratio sini over sinr. A ray is shown leaving a substance that looks like glass.
a The substance is not glass because glass always has a refractive index of 1.5.
b The substance is glass because glass always has a refractive index of 1.5
c The substance could be perspex.
d The diagram is wrong because the angle of incidence is always bigger than the angle of refraction.
22 Four rays of light are shown approaching the surface of a block of glass in air.
Which ray will be totally internally reflected?
23 When sunlight reflects off a CD, rainbow colors appear in the reflection.
The colors appear because....
a ... sunlight has a continuous black-body type spectrum.
b ... the surface of the CD is covered with a thin film.
c ... the surface of the CD is a diffraction grating.
d ... light is refracted and reflected in multiple players on the CD.
24 When the sun shines through the corner off a water filled fish tank a range of colors are seen on a distant wall.
The colors are due to....
a.... the rainbow effect.
b ... total internal reflection
c ... the fact that water is a dispersive medium.
d ... of interference in the thin glass wall of the tank.
25 To find the refractive index of a prism we need to measure....
a ... the wavelength of the light.
b ... the angle of minimum deviation.
c ... the angle of incidence.
d ... the angle of minimum deviation and the prism angle.
26 When taking measurements of angles of refraction and of incidence a laser beam is often used because...
i ... laser light has a narrow beam.
ii ... laser light monochromatic.
iii ... laser light is coherent.
Which statements are correct?
a One only
b Two only
c Two and three only
d All three reasons.
27 Two convex lenses (A and B) are shown
to scale.
The focal length of A is....
a ... much longer than B.
b ... much shorter than B.
c ... about the same as B.
d ... negative.
28 When a plane wave is reflected from a circular concave mirror the reflected wave is....
a.... a plane wave.
b.... a circular wave centered on the mirror.
c.... a circular wave centered in front of the mirror.
d.... a circular wave centered behind the mirror.
29 Which completed statement is correct?
The most convincing demonstration that light is a wave is provided by the detailed observation of....
a.... reflection.
b.... refraction.
c.... dispersion.
d.... interference.
30 For an accurate ray diagram the height selected on the diagram for the height of the object (arrow) should be....
a.... the same as the height of the lens.
b.... less than the height of the lens.
c.... the height of the actual object.
d.... none of these. The object should be drawn as a large arrow.
31 Which statement is correct?
a We only deal with systematic errors in the teaching laboratory.
b Random errors are reduced by averaging several readings.
c Errors are always a problem in physics.
d To get good marks students should do labs which have no errors.
32 The Standard Deviation is a possible measure of random error.
The advantage of using the SD is that....
a.... it is easy to calculate.
b.... it can be expressed to one significant figure.
c.... it increases if more readings are taken.
d.... it is smaller than half the range when there are a very large number of readings.
33 When using a force probe with Logger Pro it is necessary to always....
a ... fix the probe to a rigid body.
b ... make sure the data rate is set to more than 10 points per second.
c ... measure the temperature of the room.
d ... calibrate the probe.
34 Which of the following statements could be correct, and correctly expressed?
a The values were accurate to within ±30%.
b The length was 17±2.21 cm.
c The mass of the average NZ rugby player is10 kg.
d The possible absolute error in the measured value of g was ±2%
35 The lifetimes of light bulbs are being investigated. One student found that eight bulbs in his house lasted....
360 hours
381 hours
389 hours
392 hours
370 hours
392 hours
402 hours
442 hours
The lifetime of a bulb would be correctly stated as....
a.... 360 hours
b.... 440 hours
c.... 400 ± 40 hours
d.... 400 ± 42 hours
36 Similar bulbs in another house were found to last for....
209 hours
221 hours
240 hours
272 hours
290 hours
300 hours
320 hours
342 hours
The difference is probably due to....
a.... incorrect time measurements.
b.... voltage fluctuations in the power supply to the second house.
c.... a systematic error.
d.... human error.
37 A student had measured the period of oscillation of a pendulum with a stop watch. She put in her lab book that the error in each measurement was ±0.2 seconds.
To be worth an A she would have got the error by....
a.... finding standard deviations for all readings.
b.... using the average human reaction time which is ±0.2 seconds.
c.... repeating at least one measurement five times and finding half the range.
d.... finding the difference between her values and the true period.
38 A computer calculation gives the area under an acceleration-time graph plotted in meters per second versus seconds as 23.4.
The units of the area are....
a ... meters.
b ... meters per second.
c ... meters squared.
d ... none of the above.
39 The length of a stick of French bread is to be found with a meter rule. Many loaves are avaiilable.
The random error in the single final value will be due mainly to....
a ... variations in stick length.
b ... variations in room temperature.
c ... an inaccurate ruler ( ± 0.5 mm).
d ... mistakes by the student.
40 Which statement is the most appropriate, given our current understanding?
a The laws of physics apply only in the laboratory.
b The laws of physics are rules that apply to a mathematical model of the world.
c The laws of physics determine how the physical world behaves.
d The laws of physics are the only true things we know about the world.
Question 1 [Data based question]
A semicircular perspex block is shown with a narrow beam of light from a small torch passing through the exact center of the circle. This simple equipment is commonly used in student laboratories to investigate at first hand the relationship between the angle of incidence and the angle of refraction.
.
a Outline one method by which the angles of incidence and
refraction can be found.
[1 mark]
b Give two reasons why it might have been better to use a laser pointer instead of the torch as a light source.
[2 marks]
c Copy and complete the result table. Include errors in both sine i and sin r for angles of 12 and 83 degrees.
[3 marks]
d Draw a graph of sin i versus sin r on graph paper.
Include error bars for both sin i and sin r for angles of 12
and 83 degrees. Use a ruler to put in any lines on the graph.
[4 marks]
e Find the refractive index of perspex.
[1 mark]
f Estimate the error in your value of refractive index.
[2 marks]
g A graph of angle i versus angle r is shown a right.
Explain why a small error in angle i would lead to different errors in angle r at 12° and 83°.
[2 marks]
Question 2 [Interference and diffraction]
1 Waves pass through two slits a distance d apart. An interference pattern is formed in the region to the right of the barrier.
a The point x marked on the central line is on a line of reinforcement in the interference pattern. On either side of this center line there are lines along which no waves are present. The name usually given to these 'no wave' lines is....
[1 mark]
b The interference pattern can be used to find the wavelength of the waves. Copy the diagram and mark the lengths which you would measure to find the wavelength. Label the lengths d.... x.... and.... L, where the symbols have their usual meanings.
[3 marks]
The double slit experiment was carefully performed and reported for Sunlight by Thomas Young, an English medical doctor who was interested in vision. Students often do the same thing using a line filament bulb and two slits about 0.1 mm apart.
c Draw and label an experimental arrangement which could be used to measure the wavelength of red light using a double slit and a suitable light bulb.
[2 marks]
d What alteration in the slits would you suggest to make the measurements more accurate? Why might this suggestion not be practical?
[2 marks]
e What difference if any would a student notice if they were to look at a green light and not a red one?
[1 mark]
f The student now substitutes three equally spaced slits for the two used previously. What differences would he notice?
[2 marks]
g The grooves on a compact disc (CD) act as a reflection diffraction grating. Draw a simple labeled diagram of the experimental arrangement you might use to find the separation of the grooves on a CD. What light source would be most satisfactory?
[2 marks]
i The wavelength of laser light is 6.3 x 10-7 meters. The fringe separation when using the CD as a grating is 15 cm and the distance L is 25 cm. Find the separation of grooves on the CD.
Show your working.
[2 marks]
Part 1
a Two bodies collide. Body A is twice the mass of body B.
The force-time graph for the force on B is shown. Sketch the force - time graph for body A on the same axes.
[1 mark]
b Outline briefly one experimental demonstration of
Newton's so called "third law".
[2 marks]
c Find the total momentum before the collision.
Be sure to include the units of momentum
[2 marks]
d What is the total momentum after the collision?
[1 mark]
After the collision the two masses do stick together. Find the velocity after the collision.
[1 mark]
e Find the total kinetic energy before and after the collision.
[2 marks]
f What has happened to the lost energy?
[1 mark]
Part 2
a Find the kinetic energy of a 70 kg person running at 10 m/s.
[1 mark]
b A person is likely to survive running in to a tree at 10 m/s. When a person falls the potential energy (mgh) is converted to kinetic energy. How far would a person have fallen if their kinetic energy on impact with the ground was the same as running into a tree?
[2 marks]
c A person falls from an upper balcony which is 15 meters above an ashphelt drive. Comment on their chances for survival on the basis of the physics of the situation.
[1 mark]
d Outline a simple demonstration the KE (not momentum) is associated with damage in collisions.
[2 marks]
Part 1
A ball is suspended on a rubber band from a force probe. It hangs above a motion detector placed on the floor (not shown). The force probe is moved up and down by hand and graphs are plotted in MacMotion.
a How should the motion detector be placed so that position and time data will be recorded for the whole motion?
[1 mark]
b Why is the motion detector sometimes called a "BAT"?
[1 mark]
c A distance-time graph is shown. What is the displacement of the ball after the first second?
[1 mark]
d At what times is the velocity positive?
[2 marks]
Part 2
Mechanics
A 24 kg drum of water is placed on a trolley and pushed across a level floor with a hand held force probe.
The force measured by the force-probe is F.
The net unbalanced force on the drum is (F - f) where f is the friction force.
a Where should the motion detector be placed to record the displacement of the drum? (Show the position you select on a diagram on your answer paper.)
[1 mark]
A velocity-time graph is shown
b What is the maximum velocity of the trolley?
[1 mark]
c Estimate the distance traveled between 2 and 6 seconds (after the accelerating force was removed).
[2 marks]
d Find the negative acceleration of the trolley between 2 and 6 seconds.
[1 mark]
e Find the friction force acting on the trolley during this time (from 3 to 6 seconds).
[2 marks]
The force-distance graph is shown
f Explain how to find the net work done on the drum ....... allowing for the effect of friction.
[2 marks]
Part 1
A ball is bouncing across a level floor.
a.... write down the equation of the trajectory for one bounce.
[1 mark]
b What is the acceleration of the ball at the point A on the diagram above?
[1 mark]
c At what points during the motion is energy lost as heat (neglecting air resistance)?
[1 mark]
d Copy the table. By reading the heights from the graph enter maximum heights in the table for the first five bounces.
Be sure to include errors in the table as.± ... for each entry.... to the correct number of significant figures.
[2 marks]
Complete the table by calculating the maximum PE at the top of each bounce. Take g = 10 m/s/s and the mass of the ball as 0.25 kg.
[3 marks]
e Write down the loss in kinetic energy between bounce 2 and 3.
[1 mark]
Part 2
a Show that the coefficient of restitution, which is the ratio of speeds just after and just before impact is given by the square root of the ratios of the maximum heights.
Show your working
[3 marks]
b From the values in the table find the coefficient of restitution for each of the first four bounces.
[2 marks]
Is the coefficient constant within errors.
[1 mark]
Part 1
A wave is shown approaching a shallow region in a ripple tank. The wave is moving from left to right. The wave will refract into the shallow region and some energy will reflect from the interface between the deep and the shallow water.
a Draw waves in the tank to show both the reflection and refraction.
[2 marks]
b A circular wave is expanding in a ripple tank. Show the wave after reflection from the plane mirror and from the circular mirror.
[2 marks]
Part 2
A student holds a double concave lens in front of them and looks at the reflection of a ceiling light.
a They see four reflections at first but after a few minutes they see just two? There are just two. Why might they have seen four when they first looked?
[1 mark]
b Explain with the aid of diagrams how the image (or images) are formed. Your diagrams will show where the images are.
Describe the image(s) on your diagrams.... real or virtual.... inverted or upright ?
[3 marks]
c A meniscus lens with both surfaces concave upwards is substituted for the double concave lens. Describe any differences in the images seen in reflection.
[2 marks]
Part 3
A double convex lens has a focal length of 40 cm.
a Explain briefly how to measure the focal length.
[1 mark]
b By drawing ray diagrams or otherwise locate and describe the images formed by the convex lens of focal length 40 cm when the object distance is 35 cm and when it is 30 cm.
[4 marks]