Moment of Force and Torque of a Couple

Four forces namely gravitational force, normal force, frictional force, and driving force act on a wheel. The direction of the frictional force and driving force are as shown in the figure.

Which force that exerts a turning effect about the axle?

• Gravitational force

• Normal force

• Frictional force

• Driving force

The frictional force acting on the wheel is 24 N and the diameter of the wheel is 80 cm.

What is the moment caused by the frictional force on the wheel?

• 9.6 Nm, clockwise

• 9.6 Nm, anti-clockwise

• 19.2 Nm, clockwise

• 19.2 Nm, anti-clockwise

Charlie and his dad are sitting on a seesaw as shown in the figure.

Given Charlie's weight is 300 N and he sits 2.0 m away from the fixed point, what is the moment of force generated by Charlie?

• 150 Nm, clockwise

• 150 Nm, anti-clockwise

• 300 Nm, clockwise

• 600 Nm, anti-clockwise

Charlie and his dad are sitting on a seesaw as shown in the figure.

Given Charlie's dad's weight is 600 N and he sits 1.5 m away from the fixed point, what is the moment of force generated by Charlie's dad?

• 400 Nm, clockwise

• 600 Nm, anti-clockwise

• 900 Nm, clockwise

• 900 Nm, anti-clockwise

Charlie's weight is 300 N and he sits 2.0 away from the left side of the fixed point. Charlie's dad's weight is 600 N and he sits 1.5 m away from the right side of the fixed point.

What is the total moment of force experienced by the seesaw?

• 300 Nm, clockwise

• 900 Nm, anti-clockwise

• 900 Nm, clockwise

• 1200 Nm, anti-clockwise

Which factor is NOT the criterion of a couple?

• Forces with the same magnitude.

• Forces in the opposite direction.

• Forces acting on the pivot.

• Forces with no intersection of their action line.

Which statement is correct due to the definition of torque of a couple?

• The product of one of the forces and perpendicular distance to the pivot.

• The product of one of the forces and the perpendicular distance between the forces.

• The product of the moment of force and perpendicular distance to the pivot.

• The product of one of the moment of force and the perpendicular distance between the forces.

Given the magnitude of force F is 30 N and the distance s is 25 cm, what is the torque produced by on the circle?

• 7.5 Nm, clockwise

• 15 Nm, clockwise

• 15 Nm, anti-clockwise

• 750 Nm, anti-clockwise

Which pair of forces is a couple?

• F1 and F4

• F2 and F3

• F3 and F6

• F5 and F6

What is the torque exerted by the couple of 10 N forces to the square?

• 0.8 Nm, clockwise

• 0.8 Nm, anti-clockwise

• 8.0 Nm, anti-clockwise

• 80 Nm, clockwise