Moments
This is the turning effect of a force around a pivot.
the moment
This is a simple machine made from a rigid bar that rotates around a pivot.
a lever
This is the equation used to calculate pressure.
p = f/a
This happens to water pressure as depth increases.
increases
This is the force exerted by air particles pressing on a surface.
atmospheric pressure
In a lever, this is the point around which the lever rotates.
the pivot
This term describes the turning effect produced by a force on a lever.
moment
What happens to pressure when the same force is applied over a larger area?
pressure decreases
Water pressure increases with depth because of the weight of the __________ above.
water
Atmospheric pressure is caused by the weight of __________ pressing down on the Earth.
air
A force of 10 N is applied 2 m from a pivot. Calculate the moment.
20 Nm
A force of 15 N is applied 0.4 m from the pivot. Calculate the moment.
6Nm
A force of 50 N acts on an area of 10 m². Calculate the pressure.
5Pa
A diver swims deeper in the ocean. Describe what happens to the pressure on the diver.
pressure increases as the diver goes deeper
As a person climbs a mountain, describe what happens to atmospheric pressure.
Atmospheric pressure decreases with increasing altitude
Explain why pressure increases when the same force is applied to a smaller area, and give an example.
Pressure increases because pressure = force ÷ area, so a smaller area leads to greater pressure
Explain how a lever can be used to lift a heavy object with a smaller force.
A lever increases the moment by increasing the distance from the pivot, so a small force applied far from the pivot can balance or lift a large force acting closer to the pivot
Explain why snowshoes help a person walk on deep snow without sinking.
Snowshoes increase the surface area over which the force (weight) is spread, reducing pressure so the person does not sink into the snow
Explain why a dam is built thicker at the bottom than at the top.
Water pressure increases with depth, so the bottom of the dam experiences greater pressure and must be thicker to withstand the larger force
Explain why atmospheric pressure is greater at sea level than at the top of a mountain.
There is more air above at sea level, so the weight of the air is greater, leading to more particle collisions and higher pressure compared to higher altitudes where there are fewer air particles above
A diver descends deeper into water while carrying a sealed air container. Explain how both water pressure and atmospheric pressure change with depth and predict what happens to the air inside the container.
Water pressure increases with depth due to the weight of water above, while atmospheric pressure remains constant at the surface but is less significant compared to water pressure; the increasing pressure compresses the air inside the container, reducing its volume
A small gear drives a larger gear. Explain how this affects both the force (torque) and speed of rotation, and link this to how a lever works.
The larger gear rotates more slowly but produces a greater turning force (torque), because the force is applied over a larger radius; this is similar to a lever where increasing the distance from the pivot increases the moment, allowing a smaller force to create a larger turning effect
A sharp knife cuts more effectively than a blunt knife. Using the pressure equation, explain why and describe what would happen if the same force were applied with both knives
A sharp knife has a smaller contact area, so for the same force it produces a higher pressure, making it easier to cut; a blunt knife has a larger area, so the pressure is lower and it is less effective at cutting
A sealed air bubble rises from the bottom of a lake to the surface. Explain how the pressure changes and describe what happens to the volume of the bubble
As the bubble rises, water pressure decreases because there is less water above it; this causes the gas inside to expand, so the volume of the bubble increases
A sealed plastic bottle is taken up a mountain and then brought back down. Explain how atmospheric pressure changes and predict what happens to the shape of the bottle at each stage.
As the bottle is taken up the mountain, atmospheric pressure decreases, so the higher pressure inside the bottle may cause it to expand; when brought back down, atmospheric pressure increases, compressing the bottle as the external pressure becomes greater than the internal pressure