CBSE Class 9 Science Worksheet
Unit 3-Motion, Force and Work - Force and laws of motion
1.
Fill in the blanks: Momentum of a massive object at rest is _________.
2.
State True/False: When a body moves over a frictional surface, its acceleration increases with increase in friction.
A)
6
B)
0.0
3.
Fill in the blanks: When the acceleration of a body is zero then its velocity ________.
A)
increases
B)
decreases
C)
remains constant
D)
either increases or decreases
4.
A body goes from A to B with a velocity of 20 metre/second, comes back from B to A with a velocity of 30 metre/second. The average velocity of the body during the whole journey is?
A)
24m/sec
B)
25m/sec
C)
50 m/sec
D)
0
5.
The SI unit of force is?
A)
Kgm/s²
B)
m/s²
C)
j/s
D)
v
6.
Statement 1: When we pedaling the bicycle it stops because friction force acts on it.
Statement 2: Friction force always acts in the opposite direction of motion.
A)
Both statements are correct and statement 2 is the reason of staement 1
B)
Both Statement are correct but Statement 2 is not the reason for statement 1
C)
Only Statement 1 is correct
D)
Only statement 2 is correct
7.
Choose the correct option: A passenger in a moving bus tosses a coin which falls behind him. It means that the motion of the bus is ________.
A)
uniform
B)
retarded
C)
accelerated
D)
None of these
8.
Fill in the blanks: The mass of an object is a measure of its __________.
9.
A force of 6N acts on a mass of 2kg at rest for 5s. Find its momentum after 5 seconds.
10.
Which of the following situations involves the Newton’s second law of motion?
A)
(a) A force exerted by the escaping air from a balloon in the downward direction makes the balloon to go upwards
B)
(b) A force can stop a lighter vehicle as well as a heavier vehicle which are moving
C)
(b) A force exerted by a lighter vehicle on collision with a heavier vehicle results in both the (vehicles coming to a standstill)
D)
(d) A force can accelerate a lighter vehicle more easily than a heavier vehicle which are moving
11.
Fill in the blanks: Athletes rest their right foot in solid supporter, so as to get ___________.
A)
high speed
B)
equal and opposite push
C)
high momentum
D)
None of these
12.
A force of 50N acts on a mass of 12.5 kg for 4s. To calculate itsvelocity.
13.
Fill in the blanks: The force exerted on a body of mass m moving with acceleration a is ________.
14.
Choose the correct option: One should not jump out from the moving bus because of __________.
A)
inertia of rest
B)
inertia of motion
C)
inertia of direction
D)
None of these
15.
A coin placed on a card(rested at the edges of the glass) remains at rest because of
A)
Inertia of rest
B)
Two forces act on the coin which balance each other
C)
No unbalanced force acts on it
D)
All of these
16.
Complete the following statement: A canon after firing recoils due to _________.
A)
Newton’s second law of motion
B)
law of conservation of energy
C)
Newton’s first law of motion
D)
Newton’s third law of motion
17.
Action and reaction forces first
A)
act on same body
B)
act on different bodies
C)
act in same direction
D)
both option A and C
18.
The rate of change of momentum of an object is proportional to
A)
Mass of the body
B)
Velocity of the body
C)
Net force applied on the body
D)
None of these
19.
Complete the following statement: When an object undergoes acceleration ___________.
A)
its speed increases
B)
a force will act on it
C)
it will fall towards earth
D)
None of these
20.
What is the S.I. unit of momentum?
CBSE Class 9 Science Worksheet
Unit 3-Motion, Force and Work - Force and laws of motion
Answers
1.
zero
2.
Option B
3.
Option C
4.
Option D
5.
Option A
6.
Option A
7.
Option C
8.
inertia
9.
30kgm/s
10.
Option D
11.
Option A
12.
16m/s
13.
ma
14.
Option B
15.
Option A
16.
Option D
17.
Option B
18.
Option C
19.
Option B
20.
kgm/s
