Moments (Cambridge (CIE) IGCSE Physics)

The diagrams below show three beams, each is pivoted at the centre. Each beam also has two forces acting on it, as shown.

Which of the beams will rotate clockwise?

A ‘yardarm’ is a stick, hung from a string, that is used to weigh goods. Goods are placed in the pan on the left, and weights are added to the box on the right side until it balances. The weight of the pan and the box are such that the weight of the yardarm itself is entirely balanced by the pan. The yardarm is 65 cm long.

How many 0.5 N weights need to be added to the box in order to balance the yardarm?

A plank rests on two supports, as shown in the diagram. The plank is in equilibrium. Three forces act on the plank.

Which statement is true?

A corkscrew is used to open a bottle of wine.

Two forces are applied at each of the positions shown below.

Which pair of forces produces the greatest turning force?

Extended tier only

The diagram shows a door handle with three forces acting on it.

How will the door handle move?

The diagrams each show a beam resting on a pivot and being acted on by some forces. The beam is not attached to the pivot. The pivot is in the centre of the rod in each case.

Which of the beams is in equilibrium?

A wardrobe is shown tilted at a variety of angles.

In which position is the wardrobe in equilibrium?

Why are passengers not allowed to stand up on the top deck of a double decker bus?  

A uniform beam is pivoted at one end and suspended by a 200 N force as shown in the diagram.

The beam is in equilibrium.

What is the weight of the beam?

Extended tier only

A cardboard rectangle is hung from a nail as shown in the diagram.

A plumb line is also hung from the nail.

Which of the points labelled shows the centre of gravity of the cardboard rectangle?

Extended tier only

A uniform beam of wood of mass  rests on a pivot. The far left side of the wood is tied to a bolt in the floor with a length of rope with tension , such that it lies completely horizontal. An object of mass is placed with its centre of gravity on the very end of the right hand side of the beam.

The perpendicular distance from the rope to the pivot is one quarter of the beam's length.

Which expression for the mass of the beam is correct?

Extended tier only

A "V" shaped object has a sphere attached to either end of the "V" and is balanced on its point. The length of the short arm of the object is . The sphere of mass is a height  off the ground. The sphere of mass  is a horizontal distance of from the point of the shape. 

The object is in equilibrium. Which expression for is correct?