Moments and pressure Flashcards
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How does pressure depend on force and area?
Pressure=force/area. So for the same force, if the area it is acting on is larger there will be less pressure.
Give two ways of increasing pressure.
Making the area it is acting on smaller.
Increase the force.
Give two different units for pressure
N/mm2
N/m2
N/cm2
Pascals
What unit is force measured in?
Newtons(N)
Why is there pressure from gases?
Because gas molecules are constantly moving and when they hit the wall or another molecule they exert pressure
Why is there pressure from liquids?
Because liquid molecules are constantly moving and when they hit the wall or another molecule they exert pressure
What happens to a balloon in a vacuum jar?
The balloon expands because there are no particles bouncing on the outside of the balloon but there are on the inside so the balloon pressure is much greater therefore expanding it.
How does water pressure change with depth?
The pressure increases with depth because there are more water molecules above you which means there is a greater force acting on the area.
Explain how a gas changes when it is compressed
The particles bounce agains the wall and each other more frequently and therefore exert a higher pressure.
How does a hydraulic system work?
It works by using a liquid to transmit force from one place to another
How do the Magdeburg spheres work?
They work if you create a vacuum inside of the spheres. This makes the pressure on the inside unequal to the pressure on the outside(atmospheric pressure) which means there are particles hitting the wall on the outside but not on the inside making it very hard to pull apart. If the pressure in the spheres was the same as the atmospheric pressure they would just fall apart.
What is a lever?
It is a machine which multiplies the force you put in. The longer the lever the easier it is to pull the object.
What is the effort, the load and the pivot?
The effort is the force you put in.
The load is the mass that you are moving.
The pivot is the point of rotation.
Give 3 examples of levers
Wheelbarrow, scissors, bottle opener.
What is a moment ?
It is the turning force of an object
