9th Class Physics Chapter No.3 Past Paper MCQs
Chapter # 3
DYNAMICS
1. Newton’s first law of motion is valid only
in the absence of:
(A)
Force
(B)
Net force
(C)
Friction
(D) Momentum
2. Inertia depends upon:
(A)
Force
(B)
Net force
(C)
Mass
(D) Velocity
3. A body jumps out of a moving bus. There is a
danger for him to all:
(A)
Towards the moving bus
(B)
Away from the bus
(C)
In the direction of a motion
(D) Opposite
to the direction of motion
4. The mass of the body:
(A)
Decreases when accelerated
(B)
Increases when accelerated
(C)
Decreases when moving with high
velocity
(D) None
of these
5. The SI unit of momentum is:
(A) Nm
(B) Kgms-2
(C) Ns-1
(D)
Ns
6. Which of the following material lowers
friction when pushed between metal plates?
(A)
Water
(B)
Fine marble powder
(C)
Air
(D) Oil
7. Mathematically momentum is defined as:
Equation of momentum is:
(A)
P =
(B)
P = mv2
(C)
P = (mv)2
(D)
P = mv
8. The product of a mass and a velocity of a
body is called:
(A)
Torque
(B)
Force
(C)
Work
(D)
Momentum
9. A
string stretched by two equal and opposite forces of 10 N each. The tension in
the
string is:
(A)
10 N
(B)
5 N
(C)
Zero
(D) 20 N
10. Rate of change of momentum
is equal to:
(A)
Torque
(B)
Force
(C)
Work
(D) Distance
11. The unit of weight in system
international is:
(A)
Dyne
(B)
Kg
(C)
Pound
(D) Newton
12. How much acceleration
produced by a force of 100 N in mass of 50 Kg?
(A)
0.5 ms-2
(B)
20 ms-2
(C)
0.05 ms-2
(D) 2 ms-2
13. Complete the equation:
= ?
(A)
F
(B)
S
(C)
T
(D) m
14.
1 Newton is equal to:
(A)
1 Kgms-2
(B)
1 Kgms
(C)
1 Kgm-1s-1
(D) 1 Kg-1m-1s-1
15. The weight of a body is 147
N. Its mass will be: (when g= 10ms-2)
(A)
1.47
Kg
(B)
14.7 Kg
(C)
0.147 Kg
(D) 147
Kg
16. A force produces an
acceleration of 10 ms-2 in a body of mass 5 Kg. The value of force
is:
(A)
2
N
(B)
20 N
(C)
30 N
(D) 50 N
17. Two bodies of masses m1
and m2 attached to the ends of an inextensible string passing
over
a frictionless pulley such that both move vertically. The accelerations of the
bodies is: (A)
(B)
(C)
(D)
g
18. Coefficient of friction is
equal to :
(A)
(B)
Fs R
(C)
(D)
R
19. Coefficient of friction µs
between the tyre and road is:
(A)
0.2
(B)
0.6
(C)
0.8
(D) 1
20. Coefficient of friction
between glass and glass is:
(A)
0.9
(B)
1.0
(C)
0.8
(D)
0.2
21. The value of coefficient of
friction between steel and steel is:
(A)
0.05
(B)
0.09
(C)
0.9
(D) 0.8
22. Coefficient of friction
between tyre and dry road is:
(A)
0.6
(B)
1.0
(C)
0.05
(D) 0.2
23.
Which of the following relation is correct?
(A)
F = m
–a
(B)
F
=ma
(C)
F =
(D) F =
24.
A mass of 6Kg is moving with acceleration 2ms-1. Force acting on it
is:
(A)
3 N
(B)
4 N
(C)
8 N
(D) 12 N
25.
The maximum value of friction is called:
(A)
Cold
welds
(B)
Normal
reaction
(C)
Limiting
friction
(D) Kinetic friction
26.
The value of coefficient of friction between ice and wood is:
(A)
0.29
(B)
0.05
(C)
0.2
(D) 1.0
27.
The coefficient of friction between iron and iron is:
(A)
0.9
(B)
0.62
(C)
0.8
(D) 1.0
28.
The force required to move the car in a curved path is:
(A)
Centrifugal
(B)
Tension
(C)
Gravitational
(D) Centripetal
29.
When a horse pulls a cart, the action is on the:
(A)
Cart
(B)
Earth
(C)
Horse
(D) Earth and cart
30.
Which force rotates the body in a circle?
(A)
Magnetic
force
(B)
Gravitational
force
(C)
Centripetal
force
(D) Centrifugal force
31.
According to the law of conservation of momentum:
(A)
V=
(B)
V=
(C)
V=
(D) V=
32.
Formula of momentum is:
(A)
M=mv
(B)
P=mv
(C)
P= mv-1
(D) M=mv2
33.
Weight ‘w’ is equal to:
(A) w=mg
(B) w =
(C) w =
(D)
34. Vertical motion of two bodies attached
to the ends of a string that passes over a frictionle-ss pulley. Then tension
‘T’ is equal to:
(A)
(B)
(C)
(D)
35. The force that opposes the motion of
moving object is:
(A)
Weight
(B)
action
(C)
friction
(D)
momentum
36. Find the formula of centri petal force:
(A)
(B)
(C)
(D)
37. Centri petal force is directly
proportional?
(A)
(B)
(C)
v
(D)
r
38. Centri petal acceleration is a
inversely proportional?
(A)
mass of
(B)
velocity of
(C)
radius of
(D)
mass and radius of
39. The value of coefficient of friction
b/w tyre and wet road is:
(A)
0.2
(B)
0.6
(C)
0.8
(D)
0.9
40. Co-efficient of friction b/w wood and
concrete is:
(A)
0.8
(B)
0.2
(C)
0.9
(D)
0.62
41. Momentum is the product of mass and;
(A)
Speed
(B)
velocity
(C)
work
(D)
acceleration
42. The unit of force is:
(A)
Meter
(B)
second
(C)
joule
(D)
newton
43. The momentum Arm is represented by a
sign:
(A)
T
(B)
L
(C)
F
(D)
N
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