Advertisements
Advertisements
Question
The diagram in Fig shows two forces F1 = 5 N and F2 = 3 N acting at points A and B respectively of a rod pivoted at a point O, such that OA = 2 m and OB = 4 m.

Calculate:
- the moment of force F1 about O.
- the moment of force F2 about O.
- total moment of the two forces about O.
Advertisements
Solution
- Moment of force F1 about O = Force × AO
= 5N × 2m
= 10 Nm (anticlockwise) - Moment of force F2 at O = Force × BO
= 3N × 4m
= 12 Nm (clockwise) - Total moment of force at O
= clockwise moments − anticlockwise moments
= 12 Nm − 10 Nm
= 2 Nm (clockwise)
APPEARS IN
RELATED QUESTIONS
A nut is opened by a wrench of length 20 cm. If the least force required is 2N, find the moment of force needed to loosen the nut.
Less force is needed when applied at a farther distance from the pivoted point.
State the effect of force F in of the following diagram.

A rocket is moving at a constant speed in space by burning its fuel and ejecting out the burnt gases through a nozzle. Answer the following
1) Is there any change in the momentum of the rocket? if yes, what causes the change in momentum?
2) Is there any force acting on the rocket? if yes, how much?
What do you understand by the clockwise and anticlockwise moment of force? When is it taken positive?
It is easier to turn the steering wheel of a large diameter than that of a small diameter. Given reason.
A meter scale is provided at 10 cm mark and is balanced by suspending 400 g from 0 cm mark (fig.). Calculate the mass of meter scale.

State one factor on which the magnitude of a non-contact force depends. How does the magnitude of a non-contact force change along with distance?
Calculate the magnitude of the force of a couple, when the arm of the couple is 63 cm and the moment of the couple is 21 Nm.
A nut is opened by a wrench of length 25 cm. If the least force required is 10 N, find the moment of force needed to turn the nut.
