Tuesday, June 7, 2016
Monday, June 6, 2016
IX SAI S T055 SCIENCE TEST
TIME: 1 Hr TEST – IX (Set -2) M.M :30
SECTION -A
(1 MARK QUESTIONS)
Q. 1 What
do you infer from the graph where velocity-time graph is parallel to the time
axis?
Q. 2 Name
the physical quantity which is measured by the rate of change of momentum?
Q. 3 Name
the property of bodies that resists a change in their velocity.
Q. 4 Give
S.I unit of Latent Heat?
Q. 5 Mention
2 factors that need to be varied to liquefy atmospheric gases?
SECTION-B
(2 MARKS QUESTIONS)
Q. 6 A
satellite is moving in a circular orbit around the earth with a constant speed.
Is it being accelerated? Give reason for your answer?
Q. 7 A
force of 5N gives a mass “m1” an acceleration of 10
and mass
on
acceleration of 20
. What acceleration would it give if both
masses are tied together?
Q. 8 Two
balls of the same size but of different material, rubber and iron, are kept on
the floor of a moving train. Suddenly brake are applied to stop the truck.
(a) Will the ball start rolling?
Why? (b) If yes in which direction?
(c) Will the speed of both be same?
Q. 9 What
produces more severe burns, boiling water at 100°C or steam at
100°C?
Q. 10 The
difference between the boiling temperatures of two substance is 25oC.
How much will it be in Kelvin?
SECTION-C
(3 MARKS QUESTIONS)
Q. 11 Derive
second equation of motion by graphical method?
Q. 12 A
policeman wearing a bullet-proof jacket stands still on roller skates. The
total mass is 90 kg. A bullet of mass 20 gm is fired at 450 m/s is stopped by
the vest. What will be the velocity of policeman after that?
Q. 13 Two
persons manage to push a car of mass 1500 kg at a constant speed along a level
road. Another person then join them. Now the car gains an acceleration of 0.3
m/s2. With what force does each person pushes the car? (Assume that
each one pushes the car with equal force)
Q. 14 Define
Evaporation? Write 4 factors affecting evaporation. Give 2 differences between
evaporation & boiling?
Q. 15 A
boy of mass 45 kg jumps with a horizontal velocity of 5 m/s on to a stationary
cart of mass 5 kg having friction less wheels. What is his velocity as the cart
start moving?
IX SAI P09 A001 FORCE
IX
SAI P09 A001 FORCE
1.
[1]When a force acting on a
body has an equal & opposite reaction, then why should the body move at
all.
2.
[2] Define Force & Momentum
3.
[2] State the first law of motion mathematically from the mathematical expression
for the second law of motion.
4.
[2]A person is prone to more
serious injuries when falling from a certain height on a hard concrete floor
than on a sandy surface. Explain why.
5.
[3] A policeman wearing a bullet-proof
jacket stands still on roller skates. The total mass is 90 kg. A bullet of mass
20 gm is fired at 450 m/s is stopped by the vest. What will be the velocity of policeman
after that?
6.
[3] Two persons manage to push a car of mass
1500 kg at a constant speed along a level road. Another person then join them.
Now the car gains an acceleration of 0.3 m/s2. With what force does
each person pushes the car? (Assume that each one pushes the car with equal
force)
7.
[3] A boy of mass 45 kg jumps with a
horizontal velocity of 5 m/s on to a stationary cart of mass 5 kg having
friction less wheels. What is his velocity as the cart start moving?
8.
[3]A force of 5 N gives a mass
m1, an acceleration of 10 m/s 2 & on mass m2,
an acceleration of 20 m/s 2 , what acceleration would it give if
both the masses were tied together?
9.
[3]Two hockey players of opposite teams, while trying to hit a hockey ball on
the ground collide and immediately become entangled. One has a mass of 70 kg
and was moving with a velocity 5.0 m s–1 while the other has a mass
of 55 kg and was moving faster with a velocity 6.0 m s–1 towards the
first player. In which direction and with what velocity will they move after they
become entangled? Assume that the frictional force acting between the feet of
the two players and ground is negligible.
10. [3] Two objects of
masses 100 g and 200 g are moving along the same line and
direction with velocities of 4 m/ s and 1 m/s, respectively. They collide and after the collision, the first object moves at a velocity of 3 m s–1. Determine the velocity of the second object
11. [3]How much momentum will
a dumb-bell of mass 10 kg transfer to the floor if it falls from a height of 80
cm? Take its downward acceleration to be 10 m s–2.
12. [4]A bullet of mass 10 g
travelling horizontally with a velocity of 150 m/ s strikes a stationary wooden
block and comes to rest in 0.03 s. Calculate the distance of penetration of the
bullet into the block. Also calculate the magnitude of the force exerted by the
wooden block on the bullet..
13. [4] An object of mass 2 kg travelling in a straight line with a velocity of 5
m s–1 collides with, and sticks to, a stationary wooden block of
mass 4 kg. Then they both move off together in the same straight line.
Calculate the total momentum just before the impact and just after the impact.
Also, calculate the velocity of the combined object.
14.
[3, 2] State the
three Newton’s Laws of Motion. Also Prove F = ma.
15.
A car of
mass 2400 kg moving with a velocity of 20 ms-l is stopped in 10
seconds applying brakes. Calculate the retardation and the retarding force. 2 m/s2 ; -4800 N
16.
For how long
should a force of 100N act on a body of 20 kg so that it acquires a velocity of
100 m/s? 20 s
17.
A 1000 kg
vehicle moving with a speed of 20 m/s is brought to rest in a distance 50
metres:
(i) Find the acceleration. -
4 m/s2
(ii) Calculate the unbalanced force acting on
the vehicle. -
4000 N
18.
A body of
mass 5 kg is moving with a velocity of 10 m/s. A force is applied to it so that
in 25 seconds, it attains a velocity of 35 m/s. Calculate the value of the
force applied. 5 N
19.
An unloaded
truck weighing 2000 kg has a maximum acceleration of 0.5 m/s2. What
is the maximum acceleration when it is carrying a load of 2000 kg ? 0.25 m /s2
20.
Define
momentum of a body. What is the SI unit
of momentum ? State whether momentum is
scalar or vector.
21.
What is the
total momentum of the bullet and the gun before firing?
22.
Explain why,
it is easier to stop a tennis ball than a cricket ball moving with the same
speed.
23.
A
hammer of mass 500 g , moving at 50 ms-1 , strikes a nail . The nail
stops the hammer in a very short time of 0.01 s . What is the force of the nail
on the hammer? [-2500N]
24.
Calculate
the momentum of a toy car of mass 200 g moving with a speed of 5 m/s. [1
kg.m/s]
25.
What is the
change in momentum of a car weighing 1500 kg when its speed increases from 36 km/h to 72 km/h uniformly? [5000 kg.m/s]
26.
A man throws
a ball weighing 500 g vertically upwards with a speed of 10 m/s.
(i) What will be its initial momentum? [5 kg.m/s]
(ii) What would be its momentum at the
highest point of its flight? [
Zero]
27.
Slate the
law of conservation of momentum.
28.
A 60 g
bullet fired from a 5 kg gun leaves with a speed of 500 m/s. Find the speed
(velocity) with which the gun recoils (jerks backwards). [ 6 ]
29.
A 10 g
bullet traveling at 200 m/s strikes and remains embedded in a 2 kg target which
is originally at rest but free to move. At what speed does the target move off?
[ 0.99 ]
30.
A gun of
mass 3 kg fires a bullet of mass 30 g. The bullet takes 0.003 s to move through
the barrel of the gun and acquires a velocity of 100 m/s. calculate :
(i) The velocity with which the gun recoils
(ii) The force exerted on gunman due to
recoil of the gun. [ 1 ] [ 1000 ]
31.
A ball P of
mass 2 kg traveling at 2 m/s has a collision with another identical ball Q at
rest .Ball P stop and Q starts moving. Calculate the velocity of Q after
collision. [ 2 ]
32.
A boy of
mass 50 kg running at 5 m/s jumps on to a 20 kg trolley traveling in the same
direction at 1.5 m/s . What will be their common velocity? [ 4]
33.
A girl of
mass 50kg jumps out of a rowing boat of 300 kg on to the bank, with a
horizontal velocity of 3 m/s. With what velocity does the boat begin to move
backward? [ 0.5 ]
34.
A truck of
mass 500 kg moving at at 4 m/s collides with another truck of mass 1500 kg
moving at 2 m/s in the same direction. What is their common velocity just after
the collision if they move together? [ 2.5
35.
State First
,Second and Third laws of motion:
36.
A 8000 kg engine pulls a train of 5 wagons, each
of 2000 kg, along a horizontal track. If the engine exerts a force of 40000 N and
the track offers a friction force of 5000 N, then calculate:
(a)
the net accelerating force;
(b)
the acceleration of the train; and
(c)
the force of wagon 1 on wagon 2.
37.
Two
balls A and B have equal masses but their velocities are v and 2v, respectively.
What is ratio momentum of A to that B? ( 1:2)
38.
An automobile vehicle has a mass of 1500 kg. What
must be the force between the vehicle and road if the vehicle is to be stopped
with a negative acceleration of 1.7 m s–2?
39.
A bullet of mass 25 gm moving with a speed of 100
m/s pierces a bag full of sand kept
adjacent to a wall. The bullet stops in the bag after 0.05 second. Find :
(a) The
acceleration of the bullet (assuming uniform)
(b) The
force exerted by the sandbag on the bullet
(c) The
distance covered by the bullet before coming to rest.
40.
A hockey ball of mass 200 g travelling at 10 m s–1
is struck by a hockey stick so as to return it along its original path with a velocity
at 5 m s–1. Calculate the change of momentum occurred in the motion
of the hockey ball by the force applied by the hockey stick.
41.
An object of mass 1 kg travelling in a straight
line with a velocity of 10 m s–1 collides with, and sticks to, a
stationary wooden block of mass 5 kg. Then they both move off together in the same
straight line. Calculate the total momentum just before the impact and just
after the impact. Also, calculate the velocity of the combined object.
42.
An object of mass 100 kg is accelerated uniformly
from a velocity of 5 m s–1 to 8 m s–1 in 6 s. Calculate
the initial and final momentum of the object. Also, find the magnitude of the
force exerted on the object.
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