5086 Science - Moments

What is the turning effect of a force?

• Acceleration

• Velocity

• Moment

• Momentum

Answer explanation

The turning effect of a force is known as Moment, which causes an object to rotate around an axis. It is not related to acceleration, velocity, or momentum.

What is the equation to calculate the moment of a force?

• Moment = Force / Perpendicular Distance

• Moment = Force x Perpendicular Distance

• Force = Perpendicular Distance / Moment

• Moment = Force + Perpendicular Distance

Answer explanation

The equation to calculate the moment of a force is Moment = Force x Perpendicular Distance, as the force is multiplied by the perpendicular distance.

What is the unit for moment?

• Nm

• Kg

• m/s

• J

Answer explanation

The unit for moment is Nm, which stands for Newton-meter.

What is the distance required when calculating a moment?

• Distance from pivot to the line of action of force.

• Distance from the line of action of force to the pivot.

• Perpendicular distance from pivot to the line of action of force.

• Distance from the pivot to the ground

What is the point where an object turn about?

• The Earth

• The moon

• The pivot

• The sun

Answer explanation

The point where an object turns about is called the pivot, which serves as the center of rotation for the object.

What is the distance from the line of action of force to the pivot called?

• Distance

• Perpendicular Distance

• Force Distance

• Pivot Distance

Answer explanation

The distance from the line of action of force to the pivot is called Perpendicular Distance, as it is measured at a right angle to the line of action of the force.

Which equation is correct to find tension T?

• (4N x 35cm) = (8N x 40cm) + (T x 10cm)

• (4N x 35cm) + (T x 50cm)= (8N x 40cm)

• (4N x 35cm) = (8N x 40cm) + (T x 50cm)

• (4N x 35cm) + (T x 10cm) = (8N x 40cm)

Answer explanation

Choose the equation where (4N x 35cm) + (T x 50cm) = (8N x 40cm), which is the correct formula to find tension T. When the system is in equilibrium, the sum of the clockwise moment is equal to the sum of anti-clockwise moment.

What is the magnitude of force F to maintain the system in equilibrium?

Answer explanation

When the system is in equilibrium (balanced), the sum of clockwise moment about a pivot is equal to the sum of anti-clockwise moment about the same pivot.
Thus,
F x 120mm = 20 N x (120mm + 380mm)

F = 83.33 N
F = 83 N in 2 s.f. as the smallest s.f. is 2.

The diagram shows a wooden beam PQ, of negligible weight, which is attached to a wall by a hinge at P and kept in a horizontal position by a vertical rope attached at Q.
The beam is 3.0 m in length.
A man of weight 600 N walks along the beam from P to Q.

What is the distance of the man from P when the tension in the rope at Q becomes equal to 500 N ?

What is the moment produced by a force of 75 N with a perpendicular distance of 1.2 m from the pivot?

Answer explanation

Moment = force x perpendicular distance

= 75N x 1.2m

= 90 Nm