Turning Effect of Forces – Online MCQs Test – Physics 9th

1. A body is in equilibrium when it has:

uniform acceleration

zero acceleration

uniform speed

uniform speed and uniform acceleration

2. Stability of a racing car is increased by:

lowering its centre of gravity

raising its centre of gravity

decreasing its width

increasing its height

3. Bunsen burner is made stable by:

increasing its length

increasing its mass

decreasing its base area

increasing its base area

4. A force of 15 N makes an angle of 60 with horizontal. Its vertical component will be:

13N

10N

15N

5. Force has:

only direction

none of these

only magnitude

both magnitude and direction

6. According to the second condition for equilibrium:

sum of all torques acting on a body is constant

sum of all torques acting on a body is zero

sum of the all forces acting on a body must be equal to zero

sum of the all, forces acting on a body must be constant

7. S.I unit of the torque or moment of force is:

Newton per second

Newton second

Newton

Newton metre

8. Head to tail rule can be used to add_______ forces.

five

two

any number of

three

9. If a body is slightly titled and does not return back to its previous position, the body is said to be in:

unstable equilibrium

none of these

neutral equilibrium

stable equilibrium

10. A right rope walker carries a long pole to:

increase his weight

keep his centre of gravity in fixed position

raise his centre of gravity

lower his centre of gravity

11. Graphical method is used for addition of:

one dimensional vector quantities

two dimensional vector quantities

three dimensional vector quantities

all of these

12. sin θ =:

base / hypotenuse

perpendicular / hypotenuse

base / hypotenuse

perpendicular / base

13. They form a couple.

two Like parallel forces of the same magnitude not acting along the same line

two unlike parallel forces of the same magnitude acting along the same line

two Like parallel forces of the same magnitude acting along the same line

two unlike parallel forces of the same magnitude not acting along the same line

14. The forces that act along opposite directions are called:

none of these

like parallel forces

parallel forces

unlike parallel forces

15. A wall hanging, buildings, bridges or any object lying in rest on the ground are some examples of:

dynamic equilibrium

inertia

static equilibrium

acceleration due to gravity

16. To form a couple, two forces must be:

separated by a distance

parallel, but opposite in direction

equal in magnitude

all of these

17. The following expression represents:

the first condition of equilibrium

Newton’s first Law of motion

Newton’s second law of motion

the second condition of equilibrium

18. The turning effect of force is called:

torque

moment of force and torque

moment of force

none of these

19. According to the first condition for equilibrium:

sum of the all forces acting on a body must be constant

sum of all torques acting on a body is constant

sum of the all forces acting on a body must be equal to zero

sum of all torques acting on a body is zero

20. States of equilibrium are:

two

four

five

three

Class 9th | Physics | Chapter 4 | Turning Effect of Forces | Online MCQs Test