9th Class Physics Chapter No.4 Past Paper MCQs
HAMZA SCIENCE ACADEMY
Physics MCQs Test Class 9th
Chapter # 4
TURNING EFFECT OF FORCES
1. Two equal but unlike parallel forces having
different line of action produce:
A.
A torque
B.
A Couple
C.
Equilibrium
D.
Neutral equilibrium
2. The number of vectors that can be added by
head to tail rule is:
A.
1
B.
2
C.
Any
number
D.
4
3. The number of perpendicular components of a
vector are:
A.
4
B.
3
C.
2
D.
1
4. A force of 10 N is making an angle of 30°
with the horizontal. Its horizontal components
will be:
A.
4 N
B.
5 N
C.
7 N
D.
8.7 N
5. A body is in equilibrium when its:
A.
Acceleration is zero
B.
Speed is uniform
C.
Acceleration is uniform
D.
Speed and acceleration are
uniform
6. Racing cars are made stable by:
A.
Increasing their speed
B.
Decreasing their mass
C.
Lowering their center of
gravity
D.
Decreasing their width
7. In a right angled triangle, length of a base
is 4 cm and its hypotenuse is 5 cm. The length
of a perpendicular is:
A.
1 cm
B.
3 cm
C.
20 cm
D.
9 cm
8. Formula for the direction of resultant force
with the help of rectangular components is:
A.
= tan-1
B.
= tan-1
C.
= sin-1
D.
= cos-1
9. Cos
is equal to:
A.
B.
C.
D.
10. tan 45
is
equal to:
A.
0.5
B.
1.732
C.
0.577
D.
1
11. The turning effects of a
force is called:
A.
Momentum
B.
Torque
C.
Pressure
D. Work
12. The SI, unit of torque is:
A.
Nm
B.
Nm-1
C.
Nm2
D. Ns
13. The perpendicular distance
between the axis of rotation and the line of action of force
is called:
A.
Torque
B.
Moment arm
C.
Momentum
D.
Work
14.
The center of gravity of an irregular shaped body can be found with the help
of:
A.
Wedge
B.
Meter rod
C.
Plum line
D. Screw
gauge
15. Point of intersection of
medians is the center of gravity of a uniform:
A.
Rod
B.
Circular ring
C.
Solid cylinder
D.
Triangular sheet
16. The center of gravity of a
uniform solid cylinder is at:
A.
Middle
point on its on axis
B.
Center of the cylinder
C.
The point of inter section of
medians
D. Center
of a plate
17. The conditions of
equilibrium are:
A.
1
B.
2
C.
3
D.
4
18. First condition of
equilibrium is:
A.
ΣF =
0
B.
Σ
= 0
C.
ΣF =
0, Σ
= 0
D. All
of these
19. A pencil is lying
horizontally is the example of;
A.
Equilibrium
B.
Stable equilibrium
C.
Unstable equilibrium
D.
Neutral equilibrium
20. An example of neutral
equilibrium is:
A.
Football
B.
Block
C.
Pencil at its tip
D.
Book on the table
21. States of equilibrium are:
A.
3
B.
2
C.
1
D. 4
22. sin 45°is
equal to:
A.
0
B.
0.5
C.
0.707
D. 1
23.
sin 45° = cos 45° =
A. 1.732
B. Undefined
C. 0.866
D. 0.707
24.
The number of perpendicular components of a force are:
A. 2
B. 4
C. 3
D. 1
25.
A force of 10 N makes an angle of 90° with x-axis. Its horizontal component
is:
A. 10 N
B. 5 N
C. Zero
D. Maximum
26.
The direction of force ‘F’ with x-axis is given by:
A.
= sin-1
B.
= sin -1
C.
= tan
D.
= tan
27.
Complete the equation:
= ________
.
A. Sin-1
B. Cos-1
C. tan-1
D. tan
28.
In a right angled triangle, length of a base is 4 cm and perpendicular is 3cm.
Then its tan
is equal to:
A.
0.8
B.
0.75
C.
1
D.
0.6
29.
If Fy = 4N and Fx = 3N, What is the magnitude of a
resultant force?
A.
7 N
B.
5 N
C.
12 N
D.
10 N
30.
The center of gravity of a triangle is at:
A. Center
B. Point of intersection of medians
C. Center of axis
D. Point of intersection of diagonals
31.
The center of gravity of a uniform _______ sheet is the point of intersection
of its
Diagonals.
A. Triangular
B. Solid cylinder
C. Circular ring
D. Square
32.
Center of gravity of a sphere is at:
A. Center of a sphere
B. Outside of a sphere
C. Radius of a sphere
D. None of these
33.
According to 2nd condition of equilibrium, must be zero:
A. Angular acceleration
B. Linear acceleration
C. Rotational force
D. Sum of forces
34.
A body is in neutral equilibrium when its center of gravity:
A. Is at its highest position
B. Is at the lowest position
C. Keeps its height if displaced
D. Is situated at its bottom
35.
The number of perpendicular components of a vector are:
A. 1
B. 2
C. 3
D. 4
36.
A couple is formed by:
A. Two forces perpendicular to each other
B. Two like parallel forces
C. Two equal and opposite forces in the
same line
D. Two equal and opposite forces not in
the same line
37.
A body is in equilibrium when its:
A. Acceleration is uniform
B. Speed is uniform
C. Acceleration is zero
D. Speed and acceleration are uniform
38.
Torque is equal to:
A.
=
B.
=
C.
= FL
D.
=
39.
The value of sin 90° is:
A.
0
B.
1
C.
10
D.
0.5
40. Which force rotates the
body in a circle?
A.
Magnetic force
B.
Gravitational force
C.
Centripetal force
D.
Centrifugal force
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