VAAL UNIVERSITY OF TECHNOLOGY
FACULTY OF APPLIED AND COMPUTER SCIENCES DEPARTMENT OF PHYSICS & NON-DESTRUCTIVE TESTING SUBJECT
: PHYSICS 1 (1st OPPORTUNITY)
CODE
: APFSG 1A
DATE
: JUNE/JULY 2016
DURATION
: 2 HOURS
EXAMINERS MODERATOR
: Mr. G.S. NKOSI : Mr. M.L. MBANDEZI
MARKS: TOTAL MARKS : 108 FULL MARKS : 100
INSTRUCTION: 1. 2. 3. 4.
Answer all questions. Question can be answered in any order, but subsections must subsections must be kept together. Non-Programmable calculators Non-Programmable calculators may be used. When doing calculations, give the final answer to at least two decimal places.
This question paper consists of 9 - typed pages, pages, including Information sheet, and Front Page.
DO NOT TURN THIS PAGE BEFORE PERMISSION IS GRANTED
PHYSICS 1
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OPPORTUNITY
QUESTION 1: MULTIPLE CHOICE [UNIT 1 19] [3 x 10 = 30] –
Write the correct answer for each of the following in your answer book. (Example 1.1. A) 1.1
Absolute zero on the Celsius temperature temperatu re scale is 273,15 on the Fahrenheit temperature scale? A B C D E
1.2
459,67 0 F 549,27 0 F 363,67 0 F 427,67 0 F 527,27 0 F
A box is pulled pulled across a rough surface surface at constant constant velocity A ball rolls down an inclined plane A physics student stretches a spring A projectile falls towards the surface of the earth A child pulling a toy across a rough surface causing it to accelerate
The electric potential at a certain point in space is 12 V. What energy of V. What is the electric potential energy a 2 C charge placed at that point? A B C D E
1.4
C . What is this temperature
In which which one of the following situations is zero net work done? A B C D E
1.3
0
6 J 24 J 6 J 24 J 10 J
In an decay , the t he reaction is that a parent nucleus
A Z
X produces a daughter nucleus D
particle. The symbol describing the daughter nucleus is together with the particle A B C D E
A * Z A 4 Z 2 A4 Z 2 A2 Z 1 A4 Z
D
D D
D D
1
PHYSICS 1
“APFSG1A”
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2016 – JUNE/JULY JUNE/JULY - EXAM
OPPORTUNITY
–15 1.5. The nucleus of an atom has an approximate radius of 4.80 10 –15 m. If the nucleus contains 45 protons, how many neutrons does the nucleus contain?
A. B. C. D. E.
1.6
45 19 4 128 64
Note the following situations: F F
F
M
M
Cas e 1
M
Cas e 2
Case Case 3
In which case will the magnitude of the normal force on force on the block be equal to (Mg ( Mg – – F sin F sin θ)? A. B. C. D. E.
Both cases 1 and 3 Both cases 1, 2 , and 3 Case 1 only Case 2 only only Case 3 only
1.7. Two uncharged conducting spheres, A and B, are suspended from insulating threads so that they touch each other. While a negatively negatively charged rod is held near, but not touching sphere A. And sphere B is moved away from sphere A, how will the spheres be charged ?
A
Sphere A A. B. C. D. E.
0 –
+ 0 +
Sphere B + + –
0 0
2
B
PHYSICS 1
“APFSG1A”
1.8. The half-life of
200 79 Au 12
1
st
OPPORTUNITY
2016 – JUNE/JULY JUNE/JULY - EXAM
is 2.88 10 3 s. What is the mass of a sample of of
200 79 Au
that has an
activity of 1.42 10 Bq? A. B. C. D. E.
9.80 109 g 5.89 1012 g 1.96 106 g 2.41 103 g 2.78 1015 g
1.9. Complete the following following statement: statement: The transfer transfer of heat heat by convection will occur A. B. C. D. E.
Only in metals. With or without the presence of matter. Only in a vacuum. Only in the presence of a fluid. Only in the presence of a liquid.
1.10 Ball A is dropped from rest from a window. At the same instant, ball B is thrown downward; and ball C is thrown upward from the same window. Which statement concerning concer ning the balls after their release is necessarily necessarily true if air resistance is neglected? A. B. C. D. E.
All three balls strike strike the ground at at the same time. All three balls have the same velocity at any instant. At some instant after it is thrown, the acceleration of ball C is zero. All three balls reach the ground with the same velocity. All three balls have the same acceleration at any instant.
3
PHYSICS 1
“APFSG1A”
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OPPORTUNITY
2016 – JUNE/JULY JUNE/JULY - EXAM
QUESTION 2: LEARNING UNIT 1 7 [23] –
2.1. State Huygens’ Principle. Principle.
[2]
2.2. A wave causes a displacement y that is given in meter according to y = sin (5πx + πt), where t and x are expressed in seconds and meters, r espectively. espectively. Determine a. b. c. d. e. 2.3
Amplitude Frequency Wavelength Speed of the wave Direction of the wave
[1] [2] [2] [2] [1]
A standing wave wave experiment experiment is performed performed to determine determine the speed of waves in a rope. The standing wave pattern shown below is established in the rope. The rope makes 90.0 complete vibrational cycles in exactly one minute. Calculate the speed of the waves. [4]
2.4. When a diffraction diffraction grating is used with light light that has a wavelength wavelength of 621 nm, a third order order maximum is formed at an angle of 18.0 degree. How many lines per centimetre does this grating have? [5] 2.5. A convex mirror produces produces an image image that is half half the size of an object. object. The object is is 13 cm in front of the mirror. Calculate the radius of curvature of the mirror? [4]
4
PHYSICS 1
“APFSG1A”
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OPPORTUNITY
2016 – JUNE/JULY JUNE/JULY - EXAM
QUESTION 3: LEARNING UNIT 8 12 [24] –
3.1.
State Newton’s Law of Universal gravitation in words. words.
[2]
3.2. A sailboat race course consists consists of four legs, defined defined by the displacement displacement vectors vectors A, B, C, and D, as the drawing indicates. The magnitudes of the first three vectors are A = 3.20 km, B = 5.10 km, and C = 4.80 km. The finish line of the course coincides with the starting line. Using the data in the drawing, find the distance of the fourth leg and the angle θ . [7]
3.3. The figure below shows a tourist being chased by an angry bear, and is running towards his car at constant speed 4 m.s -1. The bear is running at constant constant speed of of 6 m.s-1 and is 30 m behind the tourist. Calculate how far the tourist has run before the bear catch him? [5]
30m
3.4. Box of mass 4 kg and Box Box of mass 2 kg are connected connected to each other other as shown in in the figure below. The friction coefficient between the 4 kg box and the surface is 0.12. Assuming pulley to be massless, calculate the acceleration acceleratio n of the two boxes [5]
5
PHYSICS 1
3.5.
“APFSG1A”
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OPPORTUNITY
2016 – JUNE/JULY JUNE/JULY - EXAM
A fireworks fireworks rocket is moving moving at a speed of 30m/s. The rocket rocket suddenly suddenly breaks up into two pieces of equal masses and they fly off with velocities v1 and v2 as shown in the figure. Calculate the magnitudes of v1 and v2. [5]
QUESTION 4: LEARNING UNIT 13 19 [31] –
4.1.
State Pascal’s principle principle
4.2
Two positive charges and one negative charge are fixed to corners of a square, as shown in the diagram. Each side of a square is 10 cm and the charges Q 1 = 7μC, Q2 = 7μC, and Q3 = – = – 7μC.
a. b.
[2]
Calculate the magnitude and direction of the net electric field at an empty corner Calculate the amount of work done as Q2 is moved to empty corner
6
[7] [5]
PHYSICS 1
“APFSG1A”
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OPPORTUNITY
2016 – JUNE/JULY JUNE/JULY - EXAM
4.3.
Determine the equivalent equivalent resistance between the points A and B of the circuit below:
[5]
4.4.
Petrol with density of 0.87 g/cm3 is flowing through a bottom region of pipeline at a speed of 2 m/s. The pipe encounters a vertical bend in the pipe raising it 6 .0 m. The cross sectional area of the pipe at the top point is half the cross sectional area at the bottom position. Calculate the pressure difference (P top – P – Pbottom ) in the pipe after and before the rise? [4]
4.5.
A 30 g ice cube at at 0°C is placed placed in an insulated box that contains a fixed fixed quantity quantity of steam at 100°C. When thermal equilibrium of this closed system is established, its temperature is found to be 23°C. 23°C. Determine the original original mass of the steam at 100 °C. [4] steam ice cube
4.6.
Determine the binding energy for
4 2
He (mass = 6.6447 x 10 -27 kg).
[4]
___________________ _____________________________ ___________________ ____________ ___ END ___________________ ____________________________ ________________ _______
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“APFSG1A”
PHYSICS 1
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2016 – JUNE/JULY JUNE/JULY - EXAM
OPPORTUNITY
INFORMATION SHEET Acceleration due due to gravity Universal Gravitational constant Density of water Weakest audible sound Coulomb’s constant Speed of light Conversion Conversion factor Hydrogen atomic mass Neutron atomic mass Area of circle Atmospheric Pressure Pressure Specific Heat Capacity of ice Specific Heat Capacity of Glass Specific Heat Capacity of water Latent Heat of fusion Latent Heat of Vapour Refractive Index of Water Refractive Index of Air
g = 9. 9.80 m.s-2 G = 6.672 x 10-11 N.m2/kg2 1.00 x 103 kg.m-3. Water = 1. Io = 1. 1.00 x 10-12W/m2 k = 8.99 x 109 N.m2.C-2 c = 3.00 x 108 m.s-1 1 u = 931. 931.5 MeV 1.673 534 x 10 -27 kg 1.674 927 x 10 -27 kg 2 r Patm=101. =101.325 kPa cice = 2000 J.kg-1.K-1 cglass = 840 J. kg -1. K-1 cwater = 4186 J. kg -1.K-1 Lf = 33.5 x 10 4 J.kg-1 Lv = 22.6 x 10 5 J.kg-1 n = 1.33 n = 1.00
: : : : : : : : : : : : : : : : : :
FORMULA SHEET y A sin( 2 ft f t 10dB log sin (m
2 x
F
v
)
m / L
sin m
I I o
1 ) 2 W
E
v ; n 1,2,3,... 2 L
T 1
f n n
W nc KE PE
f
d o
m
d i d o
1 d i
r
Q mcT ;
v 2 u 2 2as
Q mL....
s ut
1
at 2
2 u v s t 2
1 1 P 1 1v12 1 gh1 P 2 2 v 22 2 gh2 2 2
v ; n 1,3,5,... 4 L
1
kq
v u at
v f
f n n
1
r 2
D
ln 2
2
V
L L0 T
W
sin 1.22
kq
N N 0e
P b P t gh
t
r 1.20 10
15
1
m A3
T ( o C )
Q=Av o
T(K) = 273 + T( C)
n d ' d ( 2 ) n1
8
f 1 R 2
5 9
( o F 32)
PHYSICS 1
“APFSG1A”
1
st
2016 – JUNE/JULY JUNE/JULY - EXAM
OPPORTUNITY
VAAL UNIVERSITY OF TECHNOLOGY
Faculty:
APPLIED & COMUTER SCIENCE
Department:
PHYSICS AND NDT
Subject:
PHYSICS 1 (1st Opportunity)
CODE
APFSG1A
Duration:
2 Hours
Examiner:
Mr. G.S. NKOSI
Moderator:
Mr. M.L. MBANDEZI
Total marks:
108
Full marks:
*Requirements:
*Instructions:
Signature Examiner: Signature Moderator:
Answer all questions
of
Date:
of
Date:
9
100
PHYSICS1 - APIFSG 1A
1
ST
OPP - MEMORANDUM
2016 – JUNE/JULY JUNE/JULY - EXAM
QUESTION 1 [3X10 = 30] 1.1 1.2 A A
1.3 B
1.4 B
1.5 B
1.6 C
1.7 C
1.8 C
1.9 D
1.10 E
QUESTION 2 [23] 2.1. Every point on a wave front acts as a source of tiny wavelets that move forward with the same speed as the wave; the wave front at a later instant is the surface that is tangent to the wavelets. [2] 2.2. a.
A=1m
b.
2 ft t f 0.5 Hz 2 x
c.
5 x 0.4m
d.
v f v 0.5 0.4 v 0.2ms 1
e.
Negative x-direction [8]
2.3.
2
(6) 4m 3 90 f 1.5 s 1 60 v f
[4]
v 1.5 4 6ms 1 2.4.
Sin m
d
d m
621 10
9
3
6.036 m 6.03 10 4 cm
Sin Sin18 1 1 Numbe 1660lines / cm Numberr of Lines/cm d 6.03 10 4 cm
[5]
2.5. m 1 f
d i d o
1 d o
f
R 2
d i md o 0.5 13 6.5cm
1 d i
f
d o d i d o d o
13 (6.5) 13 (6.5)
R 2(13) 26cm
13cm
[4]
PHYSICS1 - APIFSG 1A
MEMORANDUM
ST
1
OPP EXAM – JUNE/JULY JUNE/JULY 2016
QUESTION 3 [24] 3.1
Any two objects exert a force on each other, which is directly proportional to the product of their masses and indirectly proportional proportio nal to the square of the distance between them. [2]
3.2. R X A X B X C X 3.2 cos 40 5.1 cos 35 4.8 cos 23 D x 0 D x 6.14km R y A y B y C y 3.2 sin 40 5.1 sin 35 4.8 sin 23 D y 0 D y 3.11km 2
2
D D X D y (6.14) 2 ( 3.11) 2 6.88km tan 1
R y
2
R x
2
tan 1
3.11 6.14
[7]
26.90 0 South of East
3.3
1 1 2 2 s B 0 B t a B t s B 6t and sT 0T t aT t sT 4t 2 2 s B 30 sT 6 4t 30
15 s sT 60m t 15 s sT 4m / s
[5]
3.4.
For the 4kg mass piece (or m 1): F x m1a x T f m1a T m1 g m1a ………...(1)
For the 2kg mass piece ( or m 2)
W T m2 a m2 g T m2 a
(2)
……………………...
add (1) and (2) m2 m1 g m1 m2 a
m2 m1 g 2kg 0.12(4kg )9.8m / s 2 a 2.5m / s 2 a a m1 m2 4kg 2kg 3.5.
[5]
P P
M xi m1 1 xf m2 2 xf 2 i 1 cos300 2 cos 600 60 0.866 1 0.50 2 ……………………………………………………….(1) sin 300 2 sin sin 600 P yi P yf M yi m1 1 yf m2 2 yf 0 1 sin 0 0.50 1 0.866 2 1 1.732 2 ……………………………………….(2) xi
xf
Subs (2) into (1) 60 0.866(1.732 2 ) 0.50 2
2 30m / s and 1 51.96m / s
[5]
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PHYSICS1 - APIFSG 1A
QUESTION 4
ST
MEMORANDUM
1
OPP EXAM – JUNE/JULY JUNE/JULY 2016
[31]
4.1.
Any change in pressure applied to a completely enclosed fluid is transmitted unchanged to all parts of the fluid and the enclosing walls. [2]
4.2
a.
7 106 6.3 106 N / C E 1 k 2 9 10 2 r 1 0.1 6 q2 9 7 10 6.3 106 N / C E 2 k 2 9 10 2 r 2 0.1 q3 7 106 3.15 106 N / C 9 E 3 k 2 9 10 2 2 2 r 3 ( 0 . 1 ) ( 0 . 1 ) q1
9
[7]
E x E 1 x E 2 x E 3 x 0 6.3 10 3.15 10 cos 45 4.07 10 N / C 6
6
6
6 6 6 E y E 1 y E 2 y E 3 y 6.3 10 0 3.15 10 sin 45 4.07 10 N / C
E P E x E y 2
2
6 2 6 2 6 (4.07 10 ) (4.07 10 ) 5.76 10 N / C
4.07 10 6 E y 1 45o South of East tan tan 6 E x 4.07 10 1
b. 6 6 (7 10 ) 9 7 10 1.80 105V 9 10 2 2 0.1 d r 3 0.14 6 6 q1 q3 (7 10 ) 9 7 10 1.80 105V V f k 2 k 2 9 10 0.14 d r 1 0.1
V i k
q1
k
q3
W i f V i V f qmoving 1.80 10 1.80 10 7 10 2.52 J 5
5
12
6
[5]
PHYSICS1 - APIFSG 1A
ST
MEMORANDUM
1
OPP EXAM – JUNE/JULY JUNE/JULY 2016
4.3.
RS 4 6 10 R P R P
R9 R8 R9 R8
98
98
R4.24 R10 R4.24 R10
4.24
4.24 10 4.24 10
2.98
[5]
R s R2.29 R3 2.98 3 5.98 R R20 5.98 20 4.60 RT 5.98 R5.98 R20 5.98 20 4.4.
v top top
Abottom v bottom
Abottom vbottom
2 vbottom 4m / s 1 Abottom 2 1 1 P B v B2 gh B P T vT 2 ghT 2 2 1 P Top P Bottom (870)(2 2 4 2 ) (870)(9.8)(0 6) 56376 Pa Bottom 2 Atop
[4]
4.5. Qlost Q gained gained mLV cmT mL f cmT m 22.6 x10 5 4186 100 23m 30 33.5 x10 4 4186 30 23
[4]
m 5 .01 g
4.6.
m (2 1.673534 10 -27 2 1.674927 10 27 ) - 6.6447 10 -27 0.0522 10 -27 kg
BE mc 2 0.0503 10 - 27 3.00 10 8
2
4.70 10 12 J
13
[4]
