SET 6
I 1. Find the odd pair from the following .a) Work - Energy b) Stress - Pressure
c) Force – Momentum d) Surface Tension - Surface Energy ½
2. Dimensional analysis can be used to check the correctness of an equation.
a) Name the principle which is used to correct an equation based on dimensional analysis. ½
b) Use the principle to check the following equation whether correct or not.
i) S = ut + ½ at2 ii) E = ½ mv2 + mgh iii) t = 2p Ö(g/l) 1 ½
3. If the percentage error in measurement of radius of sphere is 2% , then what is the percentage error
in the volume. 1
[ Total 3 ½ Score]
II 1. Identify the motions of:
i) a butterfly in search of nectar. Ii) a caroms coin over a board 1
2. Draw the velocity – time graph using the following data.
Time (s) 0 5 10 15 20 25
Velocity
(m/s)
2 4 6 8 10 12
What is the acceleration in the time interval 10 – 15 sec from the graph. 1 ½
4. Derive displacement –time relation using the v-t graph. 1 ½
5. The acceleration ‘a’ in m/s2 of a particle is given by a = 3t2 + 2t + 2 , where ‘t’ is the time in
seconds. IF the particle starts out with a velocity at the end of 2 sec. 1
[ Total 5 Score]
III. 1. A vector has both magnitude and direction. Identify vectors from following.
Force , Work , Time, impulse, charge. 1
2. Find the angle between two vectors of Ā = 2ĭ + 3ĵ - 4ķ and B = 4ĭ + 5ĵ - 2ķ 1 ½
3. Is the flight of a bird a practical example of parallelogram law of vector addition. Explain with a
neat diagram. 1 ½
[ Total 4 Score]
IV. A javelin is thrown by an athlet at an angle q with the horizontal.
a) Draw the velocity – time graph for the horizontal component of the velocity of the javelin. ½
b) Arrive at an expression for the maximum height reached by it. 1 ½
c) A bomb should be dropped from an aeroplane to hit the target. Why ? 1
[ Total 3 Score]
V. a) While catching a ball the cricket player draws his hands backwards. Why? 1
b) Identify the law behind this? ½
c) Driver running a three wheeler with a speed of 36 km/hr sees a child standing in the middle of
the way and breaks the vehicle to stop in 4 seconds just in time to save the child. What is the
average retarding force on the vehicle? The mass of the vehicle is 400kg and mass of the driver is
65kg. 1 ½
[ Total 3 Score]
VI. At a curved track, an inclination is given by raising the outer side a little above the innerside.
a) What is the advantage of this situation? 1
b) If the track has a curve of radius 400m and banked at an angle 50 and given coefficient of friction
as 0.2, find the optimum speed to avoid wear and tear of the tyre. 1
c) Find the maximum permissible speed to avoid skidding in the above case. 1
d) Why does a cyclist, negotiating a curve lean his bicycle? 1
[ Total 4 Score]
VII A cat is able to land on its feet when thrown in to air.
a) Name the law behind it. ½
b) State and explain it with the help of the law. 1 ½
c) A girl has to lean toward right while carrying a bag in her left hand. Why ? 1
[ Total 3 Score]
A
B
VIII. A body is dropped from the top of a tower of height ‘h’ . h
a) Derive expressions for the total energy of the body at positions A,B and C. 2
b) Arrive at a conclusion from the above findings. 1
c) Show the variation of kinetic energy and potential energy with position C
graphically. 1
[ Total 4 score ]
IX. a) A body is taken from the surface of earth to a height ‘h’ what will happen
to its weight? ½
b) Find the ratio of the weights of a body which is taken to height and depth equal to half of
the radius of earth. 2 ½
c) No fuel is required by a satellite to keep it in orbiting (neglect air resistance). Justify the
statement. 1
d) When planets come closer to the sun they move faster and if they are away move slower.
Explain the fact with the statement of law governing planetary motion. 2
[ Total 6 score ]
X. A small metal sphere is falling through a large column of caster oil.
a) Name the force acting on the sphere. ½
b) After some time the sphere is found to attain a constant velocity. Obtain an expression for this
velocity. 2
c) Why rain drops do not acquire a high velocity even though they are falling from a great
height? 1
[ Total 3 ½ score ]
XI. A sprayer spreads a perfume as tiny particles.
a) What is the principle of its working? ½
b) State the principle. 1
c) Can this principle be used to find the velocity of a rapid flow of water in a river? Explain. 1
[ Total 2 ½ score ]
XII. A gas has two specific heat capacities.
a) Define these specific heats ? 1
b) Derive Cp – Cv = R 3
c) Write the value of Cv for a diatomic gas. 1
[ Total 5 score ]
XIII.
a) A tunnel is set up through the centre of the earth and an object is dropped into it. What is the
type of the motion executed by the object. 1
b) Find the expression for the period of oscillation of a simple pendulum for small oscillation. 2
c) What is the frequency of oscillation of a simple pendulum mounted in lift falling freely under
gravity? 1
d) A man with a wrist watch on his hand falls from the top of a tower. Does the watch give correct
time during his free fall? 1
W [ Total 5 score ]
XIV. 1. Using the formula V= (g P/r ) ½ to explain why the speed of sound in air.
a) is independent of Pressure?
b) Is increasing with temperature?
c) Is increasing with humidity? 3 score
2. A stone is dropped from the top of a tower of height 300m splashes into water of a pond near
the base of the tower. How long will it take to hear the sound of splash at the top of tower.
Given speed of sound in air is 340m/s. 2 score
[ Total 5 score ]
Source
T1 K
Sink
T2 K
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