M1 Ch8 - Moments (fundamental)

The moment of a force causes an object to

• move forward

• move backward

• stop moving

• turn about a fixed point

Where will be the centre of gravity of a uniform rod lies ?

• At its end

• At its middle point

• At its centre of its cross sectional area

• Depends upon its material

When an object is in equilibrium, which equation is true?

• Clockwise moment = anticlockwise moment

• Clockwise moment + anticlockwise moment = 0

• Clockwise moment / anticlockwise moment = 0

• Clockwise moment + anticlockwise moment = resultant force

Moment can be calculated using the equation:

• M = F × |d|

• M = F / |d|

• M = F² × |d|

• M = F / |d|²

The SI unit of moment of force is –

• m

• N

• kgf

• Nm

A boy of weight 600N sits on the see-saw as shown at a distance of 1.5m from the pivot. What is the force F required at the other end to balance the see-saw?

• 450 N

• 350 N

• 4.5 N

• 200 N

Two masses of mass 10.0 and 6.0 kg are hung from massless strings at the end of a light rod. The rod is virtually weightless. A pivot (fulcrum) is placed off center and the system is free to rotate. If the 6.0 kg mass is 4.0 m away from the pivot, how far away is the 10.0 kg mass if the system is not rotating?

• 0.42 m

• 2.4 m

• 4.8 m

• 4.2 m

Assuming the system is in equilibrium, calculate the missing distance d

• 3.4 m

• 2.8 m

• 4.4 m

• 1.6 m

The diagram shows a beam. Without any weights, the beam balances at its centre.

Three weights are hung as shown.

At which point does a load of 2 N balance the beam?

• A

• B

• C

• D