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*This question paper is CONFIDENTIAL until the examination is over CONFIDENTIAL* Physics 960
Constants value
speed of light in vacuum permeability of vacuum permittivity of vacuum
magnitude of electron charge Planck constant
atomic mass unit constant electron rest mass
proton rest mass molar gas constant Avogadro constant Boltzmann constant gravitational constant free fall acceleration
c µo o e h u me mp R L, NA k G g = = = = = = = = = = = = = = 3.00 x 108 m s-1 4π x 10-7 H m-1 8.85 x 10-12 F m-1 [1/(36 π)] x 10-9 F m-1 1.60 x 10-19 C 6.63 x 10-34 J s 1.66 x 10-27 kg 9.11 x 10-31 kg 1.67 x 10-27 kg 8.31 J K-1 mol-1 6.02 x 1023 mol-1 1.38 x 10-23 J K-1 6.67 x 10-11 N m2 kg-2 9.81 m s-2
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*This question paper is CONFIDENTIAL until the examination is over CONFIDENTIAL* Section A [15 marks]
Answer all questions in this section. 1 Which of the following physical quantities is a scalar quantity?
A Velocity B Acceleration C Electric potential D Electric field strength
2 Which of the following physical quantities have the dimensions of ML2T-1 ? A Force
B Torque C Energy
D Angular Momentum
3 Which of the following errors is a systematic error ? A Zero error
B Parallax error
C Error due to wrong measurement D Error due to non-uniformity of shape
4 The velocity of an object traveling in a straight line changes from 30 ms-1 to 15 ms-1 over a distance of 75 m. Assume that the deceleration is constant. The object will come to rest after traveling an additional distance of
A 15 m B 25 m C 35 m D 50 m
5 The figure shows a body of weight W placed on a smooth plane inclined at an angle θ to the horizontal. A force F acts horizontally on the body.
The resultant force acting downwards along the inclined plane is A W cos θ + F cos θ B W sin θ + F cos θ C W sin θ - F cos θ D W sin θ - F sin θ F W θ
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*This question paper is CONFIDENTIAL until the examination is over CONFIDENTIAL* 6 The maximum and minimum possible resultant forces for two forces acting on a particle are 10 N and 4 N respectively. The magnitudes of the two forces are
A 3 N and 7 N B 4 N and 6 N C 4 N and 10 N D 6 N and 14 N
7 The diagram shows two trolleys, X and Y, about to collide and gives the momentum of each trolley before the collision.
After the collision, the directions of motion of both trolleys are reversed and the magnitude of the momentum of x is then 2 Ns. What is the magnitude of the corresponding momentum of Y?
A 6 Ns B 8 Ns C 10 Ns D 30 Ns
8 The gravitational field strength at a point P on the Earth’s surface is numerically equal to A the change in potential energy per unit distance from P.
B the work done in bringing unit mass from infinity to P. C the force acting on any body placed at P.
D the acceleration of free fall at P.
9 Figure shows two stars of equal mass M move with constant speed v in a circular orbit of radius R about their common centre of mass.
What is the net force on each star?
A 2 2 4R GM B R Mv 2 2 C zero D 2 2 R GM X Y 20Ns 12Ns
R
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*This question paper is CONFIDENTIAL until the examination is over CONFIDENTIAL* 10 Which of the following statements is true regarding the static friction between two surfaces ?
A Static friction depends on the area of the surfaces.
B Static friction does not depend on the nature of the surfaces. C Static friction is always less than dynamic friction.
D Static friction can vary and has a maximum value.
11 The graph below shows how the force F between two atoms varies with their separation r. At equilibrium, their molecular separation is
A OX B OY C OZ D XY
12. Young ‘s modulus is the ratio of A Force to extension
B The energy stored per unit volume C Strength of the wire
D Stiffness of the wire
13. The stress-strain graphs for four types of materials are shown below.
r
F
z
O
x
y
Stress
Q P R S OStrain
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*This question paper is CONFIDENTIAL until the examination is over CONFIDENTIAL* The material that is most stiff is
A P B Q C R D S
14 In the derivation of the equation 2 3 1
c
p
, which of the following statements is not an assumption of the kinetic theory of gases?A The change of momentum of the gas molecules can be neglect B The intermolecular forces can be neglected
C The volume of the gas molecules can be neglected D The collision between gas molecules is perfect elastic
15 The figure below shows the relationship between the average translational kinetic energy Ex a monoatomic molecule of an ideal gas at absolute temperature T.
The value of Boltzman constant that can be deduced from the graph above is A b a B b a 3 C b a 2 D b a 3 2
b
a
T
XE
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*This question paper is CONFIDENTIAL until the examination is over CONFIDENTIAL* Section B [40 marks]
Answer all questions in this section
16 A wheel of radius 0.25 m with moment of inertia 2 15 .
0 kgm rotates at 150 revolution per minutes. A tangential force is applied on the rim of the flywheel and its stops after 10 revolutions.
(a) Define angular velocity.
[ 1 mark ]
(b) Determine the initial angular velocity of the flywheel in
[ 2 marks ]
(c) Calculate the angular deceleration.
[ 2 marks ]
(d) Calculate the magnitude of the tangential force
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*This question paper is CONFIDENTIAL until the examination is over CONFIDENTIAL* 17 (a) Define stress and strain for a stretched wire.
[ 2 marks ] (b) Draw stress-strain graphs for a brittle material such as steel, a ductile material such as
copper and a polymer such as rubber.
[ 2 marks ] (c)
A steel wire of length 2.5 m and cross-sectional 1.5
10
-6m
2is fixed at one end. A
load of 10 kg is hung from the free end so that the wire hangs vertically. The
Young’s modulus of steel is 2.0
10
11Pa. Calculate
(i) the stress applied
[ 2 marks ]
(ii)
the extension
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*This question paper is CONFIDENTIAL until the examination is over CONFIDENTIAL* Section C [30 marks]
Answer any two questions in this section
18 (a) (i) State the principle of conservation of linear mementum.
[2 marks]
(ii) State two laws of motion which can be used to deduce this principle in the case of collision between two bodies.
[4 marks]
(b) (i) State Newton’s Laws of motion
[3 marks] (ii) What is meant by perfect elastic collision?
[1 marks]
(c) A rocket is fixed vertically on its launching pad. Before launching is started, the mass of rocket and its fuel is 1.9 x 103 kg. During launching, gas emitted from the rocket with a velocity of 2.5 x 103 ms-1 relative to the rocket. The fuel is used at the constant rate of 7.4 kg s-1 .
(Use g = 10 ms-1)
(i) Find the thrust of the rocket.
[2 marks]
(ii) Explain why there is a time lapse between the firing and the launching.
[3 marks]
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*This question paper is CONFIDENTIAL until the examination is over CONFIDENTIAL* 19 (a) State the conditions for equilibrium of a rigid body.
[1 mark]
(b) A uniform ladder AB of length 2.5 m and weight 200 N leans against a smooth wall as shown in the diagram.
Copy the diagram and show
(i) The reaction R of the wall on the upper end A of the ladder.
[1 mark]
(ii) The normal reaction P and the frictional force F at the lower end B of the ladder.
[2 marks]
(iii) Calculate the magnitude of R, P and F
[3 marks]
(c)
A wooden block on a horizontal table is attached to a pan. As the weights are placed on the pan, tension, T acts on the block, which is balanced by the frictional force F in the opposite direction.
The frictional forces is classified into two types; static friction (limiting static friction) and dynamic friction.
(i) What is meant by limiting static friction and coefficient of limiting static friction.
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*This question paper is CONFIDENTIAL until the examination is over CONFIDENTIAL* (ii) Compare the magnitude of limiting static friction and dynamic friction. [1 mark]
(d) The diagram shows a block of mass of 20.0 kg being pulled by a load 10.0 kg. Given that the coefficient of kinetic friction between the block and surface is 0.4. Calculate the acceleration of the block and the tension in the string, assuming the g = 10 m s-2.
[5 marks]
20. (a) What is the meaning of (i) internal energy
(ii) molar heat capacity for a gas. [ 2 marks]
(b) Describe about internal energy for an ideal gas. [ 2 marks]
(c) Explain why molar heat capacity of a gas at constant pressure is larger than molar heat
capacity at constant volume. [ 3 marks]
(d) A quantity of 0.200 mole of gas enters a diesel engine at pressure of 1.04 x 105 Pa and at temperature 300 K. Assuming that it is an ideal gas.
(i) find the volume of the gas. [ 2 marks]
(ii) The gas is then compressed to 10
1
of its original volume and the pressure is increased to 5.00 x 106 Pa. Find the new temperature of the gas [ 2 marks] (iii) The gas in d(ii) is supplied with 6000J of heat energy so that it expands at constant
pressure 5.00 x 106 Pa, and its temperature rises to 2500K. Find
1. the molar heat capacity at constant pressure. [ 2 marks]
