Moments

Multiple Choice

The moment of a force causes an object to

• move forward

• move backward

• stop moving

• turn about a fixed point

Multiple Choice

Moment can be calculated using the equation:

• M = F × d

• M = F / d

• M = F² × d

• M = F / d²

Multiple Choice

The SI unit of moment of force is –

• m

• N

• kgf

• Nm

Multiple Choice

The moment of a force causes an object to

• move forward

• move backward

• stop moving

• turn about a fixed point

Multiple Choice

The figure below shows a man lifting a heavy rock using a steel bar. He pushes downwards on the end of the bar with a force F.

Which pivot positions allows the force F to be as small as possible?

• A

• B

• C

• D

Multiple Choice

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

Multiple Choice

What is the size of the moment shown by the black arrow?

• 30 Nm

• 36 Nm

• 40 Nm

• 60 Nm

Multiple Choice

What is the moment produced by the 15 N?

• 15 Nm (clockwise)
• 150 Nm (anti - clockwise)
• 1.5 Nm (anti - clockwise)
• 0.15 Nm (clockwise)

Multiple Choice

State the principle of moments.

• When a system is in equilibrium, the sum of the total clockwise moment is equal to the sum of the total anti-clockwise moment about the same pivot.

• When a system is in equilibrium, the sum of the total clockwise moment is greater the sum of the total anti-clockwise moment about the same pivot.

• When a system is in equilibrium, the sum of the total clockwise moment is less than the sum of the total anti-clockwise moment about the same pivot.

• When a system is in equilibrium, the sum of the total clockwise moment is equal to the sum of the total anti-clockwise moment about the different pivot.

Multiple Choice

Find the Force

• Force = 6N

• Force = 10N

• Force = 16N

• Force = 20N

Multiple Choice

What is the anticlockwise moment acting on this crane?

• 80,000Nm
• 100,000Nm
• 120,000Nm
• 140,000Nm

Multiple Choice

What is the moment acting on the seesaw?

• 1.6Nm
• 15Nm
• 16N
• 4Nm

Multiple Choice

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

Multiple Choice

A wrench is used to tighten a nut. A 15N perpendicular force is applied 50cm away from the axis of rotation, and moves a distance of 10 cm as it turns. What is the torque applied to the wrench?

• 7.5 Nm
• 1.5 Nm
• 750 Nm
• 150 Nm

Multiple Choice

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

• 3.4 m

• 2.8 m

• 4.4 m

• 1.6 m

Multiple Choice

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

Multiple Choice

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

Multiple Choice

The easiest way to open a heavy door  is by applying the force

• Near the hinges
• In the middle of the door
• At the edge of the door far from the hinges
• At the top of the door

Multiple Choice

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

Multiple Choice

What do we call forces applied to anything that turns?

• Minute

• Moment

• Minimum

• Monument

Multiple Choice

What is the size of the moment shown by the black arrow?

• 30 Nm

• 36 Nm

• 40 Nm

• 60 Nm

Multiple Choice

Moment (Nm) =

• Force (N) x distance (m)

• Angular Force (N°) x distance (m)

• Force (N) x perpendicular distance (m)

• Force (N) x distance (s)