phy

• speed- distance travelled in unit time.

• acceleration- change in velocity divided by time taken.

GRAPHS:

• Velocity time graph- area under graph measures distance travelled.

• Distance time graph- gradient of graph measures velocity.

NEWTONS FIRST LAW:

• Object stays stationary unless acted upon by some external force.

TERMINAL VELOCITY:

• weight downwards is=to air resistance upwards.

RESULTANT FORCE:

• Two forces are unbalanced, together are equivalent to one.

• resultant force equals mass times acceleration which is newtons 2nd law.

  NEWTONS 3rd LAW:

• for every action there is an equal but opposite reaction

• equal magnitude opposite direction.

  

  MOMENTUM:

• momentum= mass times velocity.

• resultant force=change in momentum divided by time.

IMPULSE:

• FT

• MU-MV

  AFTER COLLISION EQUALS BEFORE COLLISION.

  CENTRIPETAL FORCE:

inward force needed to make an object move in a circle.

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MOMENT OF A FORCE:

• Turning effect of a force is called moment.

  moment of force=force times distance.

CONDITION FOR EQUILIBRIUM:

• Sum of clockwise moment is equal to sum of anti-clockwise moment.

HOOKES LAW:

• If beneath its elastic limit, the extension is proportional to the load.

• load=spring constant times extension.

• F=Kx

PRESSURE:

• Pressure=force divided by area.

PRESSURE IN LIQUIDS:

• pressure=pgh

• p=density

• g=gravity

• h=depth

PRESSURE FROM AIR:

• Instrument that measures atmospheric pressure= barometer.

• pressure=pascal

• pressure difference= manometer.

GAS LAWS:

• For fixed mass of gas at constant temperature, the pressure is inversely proportional to the volume. =BOYLES LAW

• P1V1=P2V2

WORK:

• W=FD

• GPE=mgh

• KE=HALF MV SQUARED.