Pressure and moments

The amount an elastic object stretches is

• the same as the amount of force applied to it

• directly proportional to the amount of force applied to it

Force =

• spring constant x extension

• spring constant ÷ extension

• extension ÷ spring constant

• stretch x extension

The elastic limit is

• where Hooke's law starts to be followed

• the furthest that a material can be stretched

• the furthest that a material can be stretched without being permanently damaged

• when permanent damage happens

Pressure is

• Weight

• force x surface area of object providing the force

• higher if the surface area of an object is larger

• the force exerted over an area

To increase the pressure we put on the ground we could

• Stand on out tiptoes

• Lie down

• Decrease our mass

• Wear shoes with a bigger surface area

Water pressure

• is different in all directions

• increases as you go deeper

• decreases as you go deeper

• only exists in large bodies of water

If an object is less dense that water

• It will sink

• It will float

• It will displace a mass of water that is less than the mass of the object

Density is

• a measure of how compact something is

• Greater in liquids than solids

• calculated by mass x volume

• measured in pascals

If you swing round on one leg of a chair, how much more pressure do you put on one point of the floor than you would if you sat properly?

Diving can cause death because of the effects of pressure.

• True

• False