Friday, May 25, 2012
IX LINES & ANGLES : ASSIGNMENT
1.
If
two lines intersect, then prove that the vertically opposite angles are equal.
2. Prove that the sum of the interior angles of a triangle is 180ยบ.
3. If a side of a
triangle is produced, then prove that the exterior angle so formed is equal to the sum of
the two interior opposite angles.
4.
In Fig lines XY and MN intersect at O. If angle POY = 90° and a : b = 2 : 3, find c.
5. In Fig. , AB ||
CD and CD || EF. Also EA is perpendicular to AB. If angle BEF = 55°, find the values of x, y and z.
6. In Fig., if PQ
|| ST, angle PQR = 110° and angle RST = 130°, find angle QRS
Thursday, May 17, 2012
IX SCIENCE ASSIGNMENT: MATTER AROUND US
1.
[3]
(a) Define evaporation.
(b)
How increase in surface
area affects rate
of evaporation with an example.
2. Define
the following terms.
(a) Latent heat of fusion (b) Sublimation (c) Evaporation
(a) Latent heat of fusion (b) Sublimation (c) Evaporation
3. [2] Show by an activity that
the gases are highly compressible as compared to solids and liquids.
4.
[2] Convert the following temperatures to
(a) Celsius
scale (i)
313 K (ii) 370 K
(b) Kelvin
scale (i)
23° C (ii) 73°
C
5.
[3] (a) What
is meant by evaporation ?
(b) Define
latent heat of fusion.
(c) Why
should the wet clothes be spread out
while drying ?
6.
[3] With the help of a diagram explain in brief an activity to show
that particles of matter are
very small.
7.
[1]At what temperature does solid
ice and liquid water
co - exist together ?
8.
[2]What is the effect of the following on the
rate of diffusion ?
(a) temperature (b) density of liquid
9.
[5] (a) Define matter. Name the state of matter in
which the forces between the constituent particles are
(i)
Strongest, (ii) Weakest.
(b) Give reasons for the following :
(i) A liquid generally flows easily.
(ii) Ice at 0°C appears colder to the
mouth than water at 0°C. Why ?
(iii) Doctors
advise to put strips of wet cloth on the forehead of a person
having high temperature.
10.
[5] Account for the following
(a) For
any physical state, the temperature remains constant during the change of
state.
(b) Water
kept in an earthen pot becomes
cool in summer.
(c) We are able to sip hot tea from a saucer
rather than a cup.
(d) An iron rod
is solid at room temperature.
(e) When sugar crystals dissolve in water, the
level of water does not rise appreciably.
11.
[2]Why should we wear cotton
clothes during summer ?
12.
[3] Describe an activity
to show that matter is made up of small
particles.
13.
[3] Answer the following questions.
(a) Why
is ice at 273
K more effective
in cooling than
water at the same temperature ?
(b) Name
the two gases
which are supplied in
compressed form in homes
and hospitals.
(c) What
is dry ice ?
14.
[3]Explain any
three factors which
affect the rate of evaporation.
15.
[3]Give reasons :
(a) Water
kept in an earthen pot becomes
cool after some time.
(b) Ice at 0oC is more effective
in cooling than water at 0oC.
IX SCIENCE ASSIGNMENT: MOTION
1.
[1] What kind
of motion of a body is
represented by the graphs given below ?
2.
[3] (a) Write
differences between speed and
velocity.
(b)
The speed of a moving object is x
m/s . Its velocity is y m/s
What is the similarity observed ?
3.
[2] (a) Define
uniform circular motion.
(b)
Is the uniform circular motion
an accelerated motion ? Give reasons for
your answer.
4.
[5] The V-T graph of
cars A and B which
start from the
same place and
move along a straight road in the
same direction, is shown. Calculate
(i) the acceleration of car A between 0 and 8s.
(ii) the acceleration of car B between 2s
and 4s.
(iii) the points of time at which both
the cars have the same velocity
(iv) which
of the two cars is ahead after8
sec. and by how much ?
5.
[3] The velocity time graph
of a ball of mass 20g moving along a stright line on a long table is given in fig. How much force does the table exert on the ball to
bring it to rest.
6.
[1] What can
you say about
the motion of a body whose distance-time graph is a line parallel
to time-axis.
7. [3] A car starts with
velocity 10 m/s and accelerates at rate 5 m/s2 . Find the final velocity when the car has
travelled a distance 30 m.
8.
[2] A body covers
a semicircle of radius 7 cm in 5
second. Find its velocity.
9. [3] Draw a graph velocity versus time
for a body starts to move
with velocity ‘u’ under a
constant acceleration a for time
t. Using this
graph derive an expression for distance covered ‘s’ in time ‘t’.
10.
[1] State the type of motion represented by the given graph.
11.
[2] (a) Define
acceleration.
(b) A stone
describes a circular path
with a constant speed. State the type of motion of the stone.
12.
[2]Write any
two equations of motion for a
body having uniform acceleration.
13.
[3] (a) Differentiate between distance and displacement.
(b) Under
what conditions is the magnitude of
average velocity of an object equal to its average speed ?
14.
[1] “The direction in which an
object moves is given
by the direction of velocity of the object and not by the direction of
acceleration”. Give an example to justify this statement.
15. [3]The driver of a train A
travelling at a speed of 54 km/h applies brakes and retards the train uniformly. The train stops in 5s.
Another train B is travelling on
the parallel track with a speed of 36
km/h. This driver also applies the brakes
and the train retards uniformly. The train B stops
in l0 s. Plot speed - time graph for both the trains
on the same paper. Also calculate the distance travelled by each
train after the brakes were applied.
16.
[2]Four speed
- time graphs are shown below. Which graph represents the following case ?
(a) A ball thrown vertically upwards and returning to the hand of the thrower ?
(b) A body
decelerating to a constant speed and
then accelerating.
17.
[2]A girl moves with
the speed of 6 km/h for 2 h
and with
the speed of 4 km/h for the next
3 h. Find the average speed of the girl and the total
distance moved.
18.
[2]Examine the
data given below
for motion of two different
objects A and B carefully and state whether the motion of the objects is uniform
or non uniform. Give reasons.
Time Distance
travelled by Distance travelled
by
object A in m. object B in m.
9.30
a.m 10 12
9.45
a.m 20 19
10.00 a.m
30 23
10.15
a.m 40 35
10.30
a.m 50 37
10.45 a.m
60 41
11.00
a.m 70 44
19.
[2]Draw velocity
time graph for :
(a) An object moving with uniform velocity.
(b) An object moving with non
uniform retardation.
20.
[3] The motion of a body of mass
5 kg is shown in the v-t graph.
Find from graph.
(a) its acceleration
(b) the force acting on the body
(c) the change in momentum of in 2 seconds
after start
21.
[3] State three equations of motion. Which of them describes :
(i)
velocity - time relation
(ii)
position -time relation ?
22.
[3]Ali while driving to School, computes the average speed
for his trip to be 20 km/h. On his
return trip along the same route
there is less traffic and the
average speed is 30 km/h. What
is the average speed for Ali’s trip
?
23.
[2]What is uniform circular motion ? Why is it considered accelerated ?
24.
[2] Which of the
following is true for displacement ? Justify your
answer for the true statement.
(a)
It can be zero.
(b) Its magnitude is greater than the distance travelled by the object.
25.
[1]Velocity time graph for a moving body
is shown in the diagram.
What conclusion can be drawn
about the type of motion ?
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