Torque and equilibrium

A uniform horizontal beam, pivoted at its right-hand end, is in equilibrium. A force of 60N acts vertically upwards on the beam as shown.

What is the weight of the beam?

• 36N

• 40N

• 90N

• 100N

Four table lamps are shown along with the position M of the centre of mass in each case.

Which lamp is the most stable?

• A

• B

• C

• D

A uniform plank is pivoted at its mid-point. Two weights are added to the plank, one weight on each side of the pivot in the positions shown.

A vertical force is applied at point X to balance the plank. What is the size and direction of this force?

• 2N Upward

• 4N Upward

• 2N downward

• 4N downward

A uniform beam is pivoted at its centre. Two weights are placed on the beam in the positions shown and the beam is balanced by an upward force F.

What is the size of F?

• 6N

• 12N

• 30N

• 60N

The total weight of the load and the wheelbarrow shown is 600N.

What is the size of force F needed just to lift the loaded wheelbarrow?

• 350N

• 430N

• 840N

• 600N

A beam of length 40cm is pivoted at one end. The weight of the beam is 4.0N and acts at a point 20cm from the pivot. A 2.0N weight hangs 10cm from the pivot.

An upward force U is needed to keep the beam horizontal.

What is the size of U?

• 0.5N

• 1.5N

• 2.5N

• 6.0N

A car is designed to be stable.

To achieve good stability, where is the centre of mass of the car?

• above the front wheels

• above the rear wheels

• as high in the car as possible

• as low in the car as possible

A man uses clay to make a pot. He wants the pot to be as stable as possible when placed on a flat surface.

Which two features of the pot must the man consider?

• the area of the base and the height of the centre of gravity

• the density of the clay and the area of the base

• the density of the clay and the height of the centre of gravity

• the weight and the height of the centre of gravity

What affects the stability of an object?

• only its base area and the location of its centre of mass

• only its weight and its base area

• only the location of its centre of mass

• only its weight

Which chair is the least stable if the child moves?

• A

• B

• C

• D