Turning Effect of Forces (Paper 1 MCQs)

The diagram shows a decoration made by suspending objects P, Q and R from light rods M and N. The rods are horizontal. Which gives a possible combination of the masses of P, Q and R?

• P = 10 g, Q = 10 g, R = 10 g

• P = 15 g, Q = 10 g, R = 10 g

• P = 15 g, Q = 20 g, R = 10 g

• P = 20 g, Q = 40 g, R = 20 g

The diagram shows a see-saw with three identical weights near the left end and two identical weights near the right end. Positions A, B, C and D are marked on the right of the pivot. In which position can another single weight be placed to balance the see-saw?

• A

• B

• C

• D

A lamina is freely suspended from point P. The weight of the lamina is 2.0 N and the centre of gravity is at C. Given PC = 0.50 m, PQ = 0.40 m and QC = 0.30 m, the lamina is displaced to the position shown. What is the moment about P due to the weight of the lamina?

• 0.60 N m clockwise

• 0.80 N m anticlockwise

• 1.0 N m clockwise

• 1.0 N m anticlockwise

The diagram shows a uniform beam that balances at its centre without any weights. Three weights are hung as shown: 5 N at the far left, 4 N to the left of the centre, and 4 N at the far right. At which point should a load of 2 N be placed to balance the beam?

• A

• B

• C

• D

The diagram shows four empty containers (A, B, C and D) made from thin glass placed on a flat surface. Which empty container is the most stable?

• A

• B

• C

• D

What makes an object the most stable?

• High centre of gravity and small area of base

• High centre of gravity and large area of base

• Low centre of gravity and small area of base

• Low centre of gravity and large area of base

A student balances a non-uniform object on a pivot by suspending a weight near the left-hand end of the object. Where is the centre of gravity of the object?

• At A

• At B

• At C

• At D

The diagram shows a bottle containing air, water and sand in layers. More sand is added to the bottle. How might the centre of gravity move?

• From X towards Y

• From Y towards X

• From Y towards Z

• From Z towards Y