MOMENTS AND CENTRE OF GRAVITY 2

A wooden bar is pivoted at its centre so that it can rotate freely. Two equal forces F are applied to

the bar.

In which diagram is the turning effect greatest?

• A

• B

• C

• D

• 0.27 N

• 0.29 N

• 0.31 N

• 0.58 N

The diagram shows a uniform, flat metal sheet hanging freely from a nail at point A. A weight also

hangs freely on a string tied to A.

One of the labelled points is at the centre of mass of the metal sheet.

Which point is at the centre of mass?

• A

• B

• C

• D

• Move the force to the right.

• Move the heavy weight to the right.

• Move the force to the left.

• Move the pivot to the left.

• They would cause the bus to become less stable.

• They would cause the bus to slow down.

• They would increase the kinetic energy of the bus.

• They would lower the centre of mass of the bus.

• A

• B

• C

• D

• 0.27 N

• 0.29 N

• 0.31 N

• 0.58 N

A uniform rod rests on a pivot at its centre. The rod is not attached to the pivot. Forces are then

applied to the rod in four different ways, as shown. The weight of the rod can be ignored.

Which diagram shows the rod in equilibrium?

• A

• B

• C

• D

• P and Q only

• P and R only

• Q and R only

• P, Q and R

• 30 N

• 40 N

• 360 N

• 480 N