Turning forces grade 7

Multiple Choice

What is the equation for moments?

• Moment = force : distance

• Moment = mass x velocity

• Moment = force x distance

• Moment = force x parallel distance from pivot

Multiple Choice

What is the moment acting on the seesaw?

• 1.6Nm
• 15Nm
• 16N
• 4Nm

Multiple Choice

The moment of a force causes an object to

• move forward

• move backward

• stop moving

• turn about a fixed point

Multiple Choice

Turning effect of force is ________.

• momentum

• moment of force

• balancing moment

• couple

Multiple Choice

The SI unit of moment of force is –

• m

• N

• kgf

• Nm

Multiple Choice

10N is applied at a radius of 3 meters from the center of a wheel. What is the magnitude of the torque produced?

• 10 Nm

• 30 Nm

• 30 kg

• 1000 Nm

Multiple Choice

It takes 30 Nm to rotate a wheel. If you can only produce 5 N of force, what is the minimum radius at which you need to apply it?

• 30 meters

• 150 meters

• 6 N

• 6 meters

Multiple Choice

What is the force F needed to balance the bar shown?

• 3

• 4

• 6

• 8

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

A see-saw is made by resting a long plank of wood with its centre of gravity on the barrel.

A boy sits on one side of the barrel and a girl sits on the other side so that the see-saw is balanced.

Which of the following statements must be true?

• boy’s weight = girl’s weight

• distance x = distance y

• moments of the girl = moments of the boy

• moment of the girl > moment of the boy