 |
IPH401S - INTRODUCTION TO PHYSICS A - 1ST OPP - NOV 2020 |
|
|
1 Page 1 |
▲back to top |
NAMIBIA UNIVERSITY
OF SCIENCE AND TECHNOLOGY
FACULTY OF ENGINEERING
InSTEM
QUALIFICATION: INTRODUCTION TO SCIENCE, TECHNOLOGY, ENGINEERING AND MATHEMATICS
QUALIFICATION CODE: O4STEM
LEVEL: 4
COURSE CODE: |IPH401S
COURSE NAME: INTRODUCTION TO PHYSICS A
SESSION:
NOVEMBER 2019
PAPER:
N/A
DURATION:
3 HOURS
MARKS:
100
EXAMINER(S)
MODERATOR:
FIRST OPPORTUNITY EXAMINATION QUESTION PAPER
Ms Ilana Malan
Ms Oksana Kachepa
Mr Anthony Apata
INSTRUCTIONS
Answer all questions.
Write all the answers in ink.
No books, notes, correction fluid (Tippex) or cell phones allowed.
Pocket calculators are allowed.
You are not allowed to borrow or lend any equipment or stationary.
All FINALANSWERS must be rounded off to THREE DECIMAL PLACES.
All CONSTANT VALUES and FORMULAS on page 8.
THIS QUESTION PAPER CONSISTS OF 8 PAGES (Excluding this front page)
|
|
2 Page 2 |
▲back to top |
SECTIONA
This section consists of nine (9) questions. Choose the correct answer and clearly indicate
your answer.
Question 1
[3]
A student walks 8 km due south and then 12 km due west. What is the resultant
displacement?
(a)
14.422 km @ 56°
(b)
14.422 km @ 326°
(c)
11.314 km @ 146°
(d) 11.314 km @ 326°
Question 2
[3]
A mass is launched at 30° to the horizontal with initial speed 25.0 m/s. What is the
maximum height reached?
(a)
6.251 m
(b)
12.508 m
(c)
7.964 m
(d)
5.674 m
Question 3
[3]
A cannon of mass 900 kg fires a 20 kg shell at a velocity of 180 ms"?. What is the recoil
velocity of the cannon?
(a)
4 m/s
(b)
3 m/s
(c)
1 m/s
(d)
10 m/s
|
|
3 Page 3 |
▲back to top |
Question 4
[3]
A bullet of mass 30 g and travelling at a speed of 200 m st embeds itself in a wooden
block. The bullet penetrates a distance of 10 cm into the wood. What is the average
resistive force acting on the bullet?
(a) 2000 N
(b)
4000 N
(c)
2500 N
(d)
6000 N
Question 5
[4]
A locomotive with a mass of 6 t and a tractive resistance of 0.5 N / kg travels at a constant
speed of 36 km/h on a straight horizontal track. Determine the work done in 10 minutes.
(a)
176.580 MJ
(b)
153.441 MJ
(c)
839.562 MJ
(d)
993.473 MJ
Question 6
[4]
In an attempt to increase the volume of a cylinder, the gas is heated for 3 minutes at a
rate of 25 kW and an efficiency of 80 %. At a certain temperature the gas pushes an
adjustable piston 30 mm outwards. If the radius of the piston is 8 cm and pressure is
3 atm, determine the change in the internal energy of the gas.
(a)
3600183.353 J
(b)
4893064.483 J
(c)
9337402.721 J
(d)
3700750.738 J
Question 7
[3]
A sample of gas contains 3.0 X 107 atoms. What volume is occupied by the gas at a
temperature of 27°C and pressure of 120 kPa?
a)
1.512 m3
) 2.436 m3
c)
1.831 m?
d)
0.104 m?
|
|
4 Page 4 |
▲back to top |
Question 8
[3]
When a certain gas is doubled in initial volume and pressure decreases by a third, what
will the final temperature be in relation to the initial temperature?
4
(a)
T, =a"
(b)
Tz, =a24
(c)
hash1
(d)
T, ac3e
Question 9
[4]
A500 W kettle contains 500 g of water at 20°C. What time is needed to raise the
temperature of the water to boiling point?
(a)
4 min 23s
(b)
5min2s
(c)
5 min 36s
(d)
3min4s
|
|
5 Page 5 |
▲back to top |
SECTION B — TOTAL MARKS 70
This section consists of six (6) questions. Answer ALL the questions.
Question 10
[16]
10.1
Determine the magnitude and direction of the equilibrant force of the
following three forces:
(7)
70 N @ 40°
15 N @ 270°
85 N @ 120°
10.2
A non-uniform wooden bar of mass 220 g and length 1.6 m is pivoted at the
centre. Three loads of masses 15 g, 30 g and 65 g are placed on the bar and
keep it in horizontal equilibrium. 15 g is placed 18 cm from the right end of
the rod, 30 g load is 42 cm from the left end and 65 g is placed 31 cm from the
right end.
10.2.1 Determine the position of the center of mass of the bar.
(4)
10.2.2
The pivot is moved 10 cm to its left. The position of the centre of mass and all
three masses remain as in 10.2.1. The magnitude of the centre of mass, the 65 g
and the 15 g masses remain as in 10.2.1. How should the 30 g mass change to
maintain horizontal equilibrium?
(5)
|
|
6 Page 6 |
▲back to top |
Question 11
[9]
11.1
State three requirements for simple harmonic motion.
(4)
11.2
The graph of displacement x against time t for an object executing simple
harmonic motion (s.h.m.) is shown in Figure 1.
: 13.
j
t:
t
i
j
j
Figure 1
11.2.1 State atime at which the object has maximum speed.
(1)
11.2.2 State a time at which the magnitude of the object’s acceleration isa maximum. (1)
11.3
Three graphs of displacement x against time t (a), velocity v against time t (b)
and acceleration a against time t (c) of an oscillating object are shown in
Figure 2 below.
A
NOP ON
NILY
or NY
27
f
)
Figure 2
|
|
7 Page 7 |
▲back to top |
State the phase difference between:
11.3.1 displacement-time and velocity-time graphs
(1)
11.3.2 velocity-time and acceleration-time graphs
(1)
11.3.3 displacement-time and acceleration-time graphs
(1)
Question 12
[15]
12.1
A ball is thrown at an angle of 35° to the horizontal and velocity of 4 m/s from
the top of the building of height 10 m. Using the time symmetry and velocity
symmetry principles determine:
12.1.1 Maximum height reached by the ball from the ground.
(2)
12.1.2 Total time of flight.
(5)
12.1.3 The range of the ball.
(1)
12.2
12.2.1
12.2.2
A truck with a mass of 6 t drives down a slope of 1 in 8 at a constant speed of
10 km/h. The resistance to motion of the truck is 190N/KN of the weight of the
truck.
Calculate the work done by the truck in a half hour.
(6)
Determine the power required if the truck was driving on a horizontal surface. (1)
Question 13
[9]
13.1
State the principle of conservation momentum.
(2)
13.2
A ball of mass 210 g moving at a speed of 23 ms hits a wall at right angle and
rebounds at a speed of 19 m/s. The ball is in contact with the wall for 0.31 s.
13.2.1 Calculate the change in momentum of the ball.
(3)
13.2.2 Calculate the magnitude of the average force acting on the ball.
(1)
13.2.3 Determine energy lost in collision.
(3)
|
|
8 Page 8 |
▲back to top |
Question 14
[11]
14.1
Define the specific heat capacity of a substance.
(2)
14.2
A small object of mass m = 250 g and unknown specific heat capacity c, initially
at 100 °C, is placed into a body of liquid with a heat capacity of 1300J K~, initially
at 20 °C. The final equilibrium temperature is 27 °C. What is the value of c?
Ignore any heat that may be absorbed by the vessel containing the liquid.
(4)
14.3
154 g of crushed ice at -20° C is removed from a freezer and placed ina
calorimeter. Thermal energy is supplied to the ice at a constant rate of 530 W.
To ensure that all the ice is at the same temperature, it is continually stirred.
The temperature of the contents of the calorimeter is recorded every 15 seconds.
Figure 3 below shows the variation with time t of the temperature @ of the
contents of the calorimeter.
A/°C
0
25
50
75
100
125
150
175
200
tls
Figure 3
14.3.1 Determine the specific heat capacity of ice.
(3)
14.3.2 Determine the specific latent heat of fusion of ice.
(2)
Question 15
[10]
15.1
List four assumptions of the kinetic model of ideal gases.
(4)
15.2
An ideal gas is kept in a cylinder by a piston that is free to move. The gas is
heated such that its internal energy increases and the pressure remains constant.
Use molecular model of ideal gases to explain the increase in internal energy. (2)
15.3
A cylinder contains 50 L of argon gas at 18.4 atm and 127 °C. How many moles
of argon gas is in the cylinder?
(2)
15.4 The volume of the cylinder is decreased by a half at a constant temperature,
what is the new pressure of argon gas in atm and in Pa?
(2)
THE END
7
|
|
9 Page 9 |
▲back to top |
Constants:
g = 9.81 m/s?
0 K =-273.15 °C
1 atm =101325 Pa
Cwater= 4200 J/kg°C
Formulae:
average speed = —di—st—an—ce
time
average velocity = utv
work = Fs
E, =mgh
_ output x 100%
input
power =F x velocity
F
_
Amomentum
At
_ Ap
At
AU = AQ + Awork
E=mL
PiVi _ P2V>
Ti
GL
10? | kilo K | 10? | centi | c
10° | Mega | M | 10% | milli | m
10° | Giga | G | 10° | micro} u
10 | Tera | T | 10° | nano | n
10° | Peta | P | 107%*| pico |p
one year = 365.25 days
R = 8.31 J/mol K
1 m?= 1000 L
Na= 6.02 x 1073 mol -
average velocit. y = displeaicmeeement
v’ 2 = u’+2as
moment = Fs
pressure = —AF
E,= f2 ay?
Wi ork
power = +t.
m,u, +m,u, =m,v, + m,v,
p- 1
T
E=mcAT
pV =nRT
work = pAs = pAV