Download December 2012 Supplementary Exam - University of KwaZulu

University of KwaZulu-Natal, Westville
PHYS199PY
Foundation Physics
Supplementary Examination November 2012
SCHOOL OF CHEMISTRY & PHYSICS
UNIVERSITY OF KWAZULU-NATAL,
PIETERMARITZBURG CAMPUS
PHYS199 PY: FOUNDATION PHYSICS
SUPPLEMENTARY EXAM NOVEMBER 2012
DURATION: 3 HOURS
TOTAL MARKS: 180
External Examiner:
Internal Examiner/s:
Dr. V. Couling
Ms. W. Dlamini, Mr. S. Jaganath, Mr. E Obaga,
Mr. R. Webber and Mr. E. Zhandire
Instructions:
 This paper consists of 18 pages plus a multiple choice answer sheet and a
data sheet. Please make sure you have them all.
 Answer all questions on the Question paper.
 In your own interest you are requested to
* Write legibly
* Consult the accompanying Data sheet for constants and some formulae.
Question
MCQ
Mark Internal
Mark External
1
2
3
4
5
6
7
8
TOTAL MARK
TOTAL %
page 1
University of KwaZulu-Natal, Westville
PHYS199PY
Foundation Physics
Supplementary Examination November 2012
SECTION 1 Multiple Choice [20 × 3 = 60 Marks]
Each question is worth 3 marks. Show your answers on the answer sheet at the back of this paper.
1.1
1.2
100 millilitres is equivalent to which of the following?
A. 0.1 l
B. 10-6 µl
C. 1 kl
D. 0.01 ml
The motion of a particle is described in the velocity versus time graph shown in the figure.
We can say that its speed
A. increases.
B. increases and then decreases.
C. decreases.
D. decreases and then increases.
1.3
A plane has an air speed of 200 ms-1 due North, and is in a wind of 50.0 ms-1 to the West. The
plane's speed relative to the ground is
A. 206 ms-1.
1.4
C. 194 ms-1 .
D. 150 ms-1.
A car travels at 90 km/h. How long does it take for it to travel 400 km?
A. 0.225 h
1.5
B. 200 ms-1.
B. 4.0 h
C. 4.4 h
D. 4.5 h
A ball is thrown straight up with a speed of 30.0 m/s. How long does it take the ball to reach the
maximum height? (take up as positive)
A. 3.06 s
B. 6.12 s
C. 294 s
D. 0.326 s
page 2
University of KwaZulu-Natal, Westville
1.6
PHYS199PY
Foundation Physics
Supplementary Examination November 2012
X and Y are two uncharged metal spheres on insulating stands, and are in contact with each
other. A positively charged rod R is brought close to X as shown in Figure (a).
Sphere Y is now moved away from X, as in Figure (b).
What are the final charge states of X and Y?
A. Both X and Y are negative.
B. X is positive and Y is neutral.
C. X is negative and Y is positive.
D. Both X and Y are neutral.
1.7
Two point charges Q1 and Q2 of equal
magnitudes and opposite signs are positioned as
shown in the figure. Which of the arrows best
represents the net electric field at point P due to
these two charges?
A.
B.
C.
D.
1.8
A
B
C
D
For a proton moving in the direction of an electric field, its
A.
B.
C.
D.
potential energy increases and its kinetic energy increases.
potential energy decreases and its kinetic energy decreases.
potential energy increases and its kinetic energy decreases.
potential energy decreases and its kinetic energy increases.
page 3
University of KwaZulu-Natal, Westville
PHYS199PY
Foundation Physics
Supplementary Examination November 2012
1.9
The figure shows three identical lightbulbs connected to a battery having a constant voltage
across its terminals.
What happens to the brightness of lightbulb 1 when the switch S is closed?
A. The brightness remains the same as before the switch is closed.
B. The brightness will increase momentarily then return to its previous level.
C. The brightness increases permanently.
D. The brightness decreases permanently.
1.10
In the circuit shown below, four identical resistors labeled A to D are connected to a battery as
shown. S1 and S2 are switches.
Which of the following actions would result in
the GREATEST amount of current through
resistor A?
A. closing S2 only
B. closing both switches
C. leaving both switches open as shown
D. closing S1 only
1.11
A 14-A current flows into a series combination of a 3.0-Ω and a 4.0-Ω resistor. What is the
voltage drop across the 4.0-Ω resistor?
A. 42 V
1.12
B. 56 V
C. 38 V
D. 98 V
If the voltage across a circuit of constant resistance is doubled, the power dissipated by that
circuit will
A. quadruple.
B. decrease to one half.
C. double.
D. decrease to one fourth.
page 4
University of KwaZulu-Natal, Westville
1.13
B. 250 W
C. 500 W
D. 50.0 W
How much current does a 150 W light bulb running on 110 V draw?
A. 0.73 A
1.15
Supplementary Examination November 2012
5.00 A is flowing through an 10.0 Ω resistor. How much power is being dissipated?
A. 2.50 kW
1.14
PHYS199PY
Foundation Physics
B. 1.4 A
C. 15 A
D. 2.0 A
If you push a 4.0 kg mass from rest with the same force that you push a 10 kg mass
from rest,
A. both masses accelerate at the same rate.
B the 4.0 kg mass accelerates 2.5 times faster than the 10 kg mass.
C. the 10 kg mass accelerates 2.5 times faster than the 4.0 kg mass.
D. None of the above are true.
The graph in the figure below shows the x component of the acceleration of a 2.4 kg
object as a function of time (in ns). Use this graph to answer 1.16 and 1.17.
(m s-1)
(ns)
1.16
At what time(s) does the x component of the net force on the object reach its
maximum magnitude, and what is that maximum magnitude?
A. 2.0 ms, 36 N
1.17
B. 3.0 ms, 7.8 N
C. 3.0 ms, 48 N
D. 2.0 ms, 4.8 N
What is the x component of the net force on the object at time t = 0.0 ms?
A. 12 N
B. -24 N
C. 48 N
D. 36 N
page 5
University of KwaZulu-Natal, Westville
1.18
A.
B.
C.
D.
1.19
A.
B.
C.
D.
PHYS199PY
Foundation Physics
Supplementary Examination November 2012
A ray of light travelling inside a glass block (nglass = 1.52) is incident at the glass/air surface. If
the angle of incidence of this ray is 54° and the critical angle of this glass block is 41°. Which
of the following statements is correct?
The ray will be totally internally reflected and the angle of reflection is 54°.
The ray will be totally internally reflected and the angle of reflection is 41°.
The ray will emerge at the air surface and the angle of refraction is 54°.
None of the above statements are correct.
A ray of light in air is incident on an air-to-glass boundary at an angle of 30° with the normal.
If the index of refraction of the glass is 1.65, what is the angle of the refracted ray within the
glass with respect to the normal?
56°
46°
30°
18°
1.20 Which of the following statements is true about images formed by a diverging lens?
A. The image formed is real and larger than the object.
B. The image formed is virtual and smaller than the object.
C. The image formed is real and smaller than the object.
D. The image formed is virtual and larger than the object.
Total Multiple Choice = 60 marks
page 6
University of KwaZulu-Natal, Westville
PHYS199PY
Foundation Physics
Supplementary Examination November 2012
SECTION 2: ANSWER THE REMAINING QUESTIONS IN THE SPACES PROVIDED ON THE
QUESTION PAPER.
Question 1
Properties of Matter [7 marks]
1.1 What is the result of [(0.410 + 0.021) × (2.20 × 103)] + 0.70? Show your working.
[3]
1.2 Convert the following measurements to given units. Give your answers in a scientific notation.
(i)
0.01230 mm =
____________________________________ μm
[2]
(ii)
1002 W =
____________________________________ kJ.s-1
[2]
Question 2 Mechanics [7 marks]
2.1 The graph in the figure shows the position of an object as a function of time. The letters
H-L represent particular moments of time. At which moments shown (H, I, etc.) is the
speed of the object
(a) the greatest? [1]
(b) the smallest? [1]
page 7
University of KwaZulu-Natal, Westville
PHYS199PY
Foundation Physics
Supplementary Examination November 2012
2.2 The figure shows the position of an object as a
function of time. During the time interval from time
t = 0.0 s and time t = 9.0 s
(a) What is the length of the path the object followed?[2]
(b) What is the displacement of the object?
[3]
Question 3 Vectors [6 marks]
3.1 Two forces are acting on a 10kg object as shown in the diagram.
What is the magnitude of the resultant force?
[6]
page 8
University of KwaZulu-Natal, Westville
PHYS199PY
Foundation Physics
Supplementary Examination November 2012
Question 4 Kinematics [10 marks]
A flying squirrel launches itself
from the top of the tree as shown in
the diagram below.
The squirrel leaves the tree with a velocity of 6.0 ms-1at 400 relative to the level ground below
and approaches a shorter tree located 15.0 m from the point of projection.
(a) Determine the time it takes the squirrel to reach the second tree, 15.0 m away.
[4]
(b) Determine the vertical displacement of the squirrel when it lands in the second tree.
[4]
(c) Draw the vector diagram showing the FINAL VELOCITY and its components.
[2]
page 9
University of KwaZulu-Natal, Westville
PHYS199PY
Foundation Physics
Supplementary Examination November 2012
Question 5 Electrostatics [21 marks]
5.1 In the figure, charge 𝑞1 = 3.1 × 10-6 C is placed at the origin and charge 𝑞2 = -8.7 × 10-6 C is
placed on the x-axis, at x = -0.20 m.
0.20 m
0.20 m
𝑞2
P
𝑞1
(a) How many more protons than electrons does charge q1 have?
[3]
(b) When a third negative charge Q is placed at point P which is 0.20 m to the right of charge q1 it
experiences a resultant force of 1.7 N to the left. What is the magnitude of charge Q?
[ 9]
page 10
University of KwaZulu-Natal, Westville
PHYS199PY
Foundation Physics
Supplementary Examination November 2012
5.2 Suppose a region of space has a uniform electric field, directed towards the right, as shown in the
figure.
(a) What happens to the electric potential energy of an electron if;
(i)
it is moved from point A to point B.
(ii)
it is moved from point A to point C.
[3]
[2]
(b) It takes 50 J of energy to move -10 C of charge from point A to point C. What is the potential
difference between point A and C?
[2]
(c) If the horizontal distance between points A and C is 20 mm, what is the magnitude of the
uniform electric field?
[2]
page 11
University of KwaZulu-Natal, Westville
PHYS199PY
Foundation Physics
Supplementary Examination November 2012
Question 6 Current Electricity [27 marks]
6.1 For the circuit shown below, neglect internal resistance.
R1 = 6.00 Ω
I2
Vb
R2 = 10.0 Ω
I3= 1.50 A
R3 = 40.0 Ω
R1 = 6.00 Ω
(a) Calculate the total resistance in the circuit?
[3]
(b) What is the current through R2?
[2]
(c) What is the voltage across R3?
[2]
page 12
University of KwaZulu-Natal, Westville
PHYS199PY
Foundation Physics
Supplementary Examination November 2012
6.2 In the circuit shown on below, a battery is connected in series with two resistors of 2.5 Ω
and 3.5 Ω.
2.5 Ω
ε
1.3 V
r = 0.5 Ω
3.5 Ω
Determine the:
(a)
Total external resistance in the circuit
[1]
(b)
current through the battery
[3]
(c)
emf of the battery
[3]
(d)
power dissipated by the 3.5 Ω
[3]
page 13
University of KwaZulu-Natal, Westville
PHYS199PY
Foundation Physics
Supplementary Examination November 2012
6.3 For the circuit shown on the below, neglect internal resistances.
28 V
I
R
Loop 1
ε
a
4.00 A
b
6.00 Ω
Loop 2
6.00 A
3.00 Ω
Loop 3
(a) Use node a to calculate current through the resistor R.
[2]
(b) Use loop 3 to calculate the resistance R.
[4]
(c) Use loop2 to calculate the unknown emf ε.
[4]
page 14
University of KwaZulu-Natal, Westville
PHYS199PY
Foundation Physics
Supplementary Examination November 2012
Question 7 Dynamics [21 marks]
7.1 A construction worker pulls a box of tools up a smooth 37.0° inclined plane, with a force
of 700 N. The mass of the box and the tools is 40.0 kg.
(a) Draw a free-body diagram for the box.
[5]
(b) Calculate the acceleration of the box.
[4]
(c) How hard does the plane push up on the box?
[4]
(d) What will happen to the force calculated in (c), if more tools are added into the box? [2]
page 15
University of KwaZulu-Natal, Westville
PHYS199PY
Foundation Physics
Supplementary Examination November 2012
7.2 Object A weighs 40 N on Earth, and object B weighs 40 N on the Moon. The Moon's
gravity is one sixth of Earth's. Compare the masses of the objects, by finding a ratio of
M
their masses(MA ).
[6]
B
Question 8 [21 marks]
8.1
(a)
The diagram below shows an object in front of a diverging lens.
One ray is shown on the diagram below. Complete the ray diagram to show where the
image will be formed.
[3]
Object
(b)
F
F
For the diagram above, the object is placed 6.0 cm from the centre of the lens and the
focal length of the lens is 4.0 cm. Find the image position by calculation.
[3]
page 16
University of KwaZulu-Natal, Westville
8.2
PHYS199PY
Foundation Physics
Supplementary Examination November 2012
Light enters a rectangular piece of ice as shown on the
right. Calculate the angle of refraction in the ice.
(nice = 1.31)
[4]
35.0
normal
air
ice
8.3
The diagram on the right shows a light beam which is
reflected inside a solid right-angled triangular transparent
prism.
The
angle
of
incidence
is
45.
Could the prism be made of diamond? Explain your answer
with the aid of a calculation. (ndiamond = 2.42).
[4]
45
45
air
prism
45
page 17
University of KwaZulu-Natal, Westville
8.4
PHYS199PY
Foundation Physics
Supplementary Examination November 2012
The screen for an overhead projector in the lecture room has a height of exactly 1.0 m. A
lecturer has a picture on a transparency with a height of 20 cm. She wants the image to
fill the screen. The distance from the lens to the screen is 1.8 m.
(a) What type of image will be formed on the screen: real or virtual? ______________ [1]
(b) Is the lens converging or diverging? _______________________
[1]
(c) Determine the magnification of the image?
[2]
(d) Calculate the distance between the transparency and the lens.
[3]
TOTAL = 180
page 18
University of KwaZulu-Natal, Westville
PHYS199PY
Foundation Physics
Supplementary Examination November 2012
STUDENT NUMBER ___________________________________
SEAT NUMBER ______
Multiple Choice Answer Sheet
Mark the letter for best answer with a cross as shown below:
1.
(a)
(b)
Question
(c)
(d)
Answer (put a cross over the correct letter)
1.1
(a)
(b)
(c)
(d)
1.2
(a)
(b)
(c)
(d)
1.3
(a)
(b)
(c)
(d)
1.4
(a)
(b)
(c)
(d)
1.5
(a)
(b)
(c)
(d)
1.6
(a)
(b)
(c)
(d)
1.7
(a)
(b)
(c)
(d)
1.8
(a)
(b)
(c)
(d)
1.9
(a)
(b)
(c)
(d)
1.10
(a)
(b)
(c)
(d)
1.11
(a)
(b)
(c)
(d)
1.12
(a)
(b)
(c)
(d)
1.13
(a)
(b)
(c)
(d)
1.14
(a)
(b)
(c)
(d)
1.15
(a)
(b)
(c)
(d)
1.16
(a)
(b)
(c)
(d)
1.17
(a)
(b)
(c)
(d)
1.18
(a)
(b)
(c)
(d)
1.19
(a)
(b)
(c)
(d)
1.20
(a)
(b)
(c)
(d)
page 19