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

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

any number of

two

three

five

2. According to the second condition for equilibrium:

sum of all torques acting on a body is zero

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

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

sum of all torques acting on a body is constant

3. Stability of a racing car is increased by:

decreasing its width

increasing its height

raising its centre of gravity

lowering its centre of gravity

4. A body is in unstable equilibrium after slight tilt if its center of gravity:

is positioned at its bottom

remains above the point of contact

remains on one side of the point of contact

passes over the point of contact

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

Newton per second

Newton metre

Newton second

Newton

6. perpendicular / base = :

tan θ

sin θ

cosec θ

cos θ

7. Force has:

only magnitude

both magnitude and direction

none of these

only direction

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

parallel forces

none of these

like parallel forces

unlike parallel forces

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

15N

10N

13N

10. They form a couple.

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

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

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

11. A body must satisfy __________ conditions to be in equilibrium.

two

four

five

three

12. Bunsen burner is made stable by:

increasing its length

increasing its base area

decreasing its base area

increasing its mass

13. Graphical method is used for addition of:

two dimensional vector quantities

one dimensional vector quantities

three dimensional vector quantities

all of these

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

neutral equilibrium

stable equilibrium

unstable equilibrium

none of these

15. The Center of gravity of uniform square or a rectangular sheet is the:

the point of intersection of its medians

point of intersection of its diagonals

its center

the mid-point on its axis

16. The turning effect of force is called:

none of these

torque

moment of force

moment of force and torque

17. States of equilibrium are:

two

five

four

three

18. sin θ =:

base / hypotenuse

perpendicular / hypotenuse

base / hypotenuse

perpendicular / base

19. A body is in neutral equilibrium when its center of gravity:

is at the lowest position

is at its base

remains at same height

is at highest position

20. A pair of unlike parallel forces having different lines of force produce _________:

a couple

torque

unstable equilibrium

equilibrium

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