Physics Summer Y10

Density is the amount of mass per unit volume.                                                                                                                        in a solid - particles are tightly packed in a regular structure                                                                                                      in a liquid - particles are tightly packed but free to move past each other                                                                                in a gas - particles are spread out and move randomly                                                                                                 Density   P=m/V   ((Density, P, Kg/m³), (Mass, m, Kg), (Volume, V, m³))                                                                                   

What defines them 

• The particals in a solid are in a regular arragement, vibrate about a fixed position and sit very close together
• The particals in a liquid are randomly arranged, move around each other, sit close together
• The particalin a gas are randomly arranged, move quickly in all directions, are far  apart

Solid > Melts > Liquid > Evaporates/ Boils > Gass

  Soild < Freeze < Liquid < Condences < Gass

Solid >>>>>>>>>>>>>>>>>>>>>>>>>> Gass

When a material is heated or cooled, two changes may happen to the particles within the material:
Chemical bondsbetween the particalsmay form, break or stretch. There is a change in the chemical potential store of energy in the material.
The material will heat up or cool down as the particles within it gain or lose speed. There is a change in the thermal store of energy within the material                                                                                                                                                Internal energy = total amount of kinetic energy and potential enery of all the particals in the system

Energy is used to raise tempreture, partical speed up and gain kinetic energy. When something melts or boils, energy is put in to breaking the bonds holding them together, increasing the potential energy.

The conservation of energy = assuming no energy is lost to the enviroment, any energy transphered to the matterial will be distrubuted between the chemical and thermal store of the internal energy.

The specific heat capasity of a material in the energy required to raise one kiologram of the material by one degree Celcius.

^E_t = m X c x  ^0

Pressure and temprature                                                                                                                      If the volumeof a container with a gas inside stays the same, the pressure of a gas increases as its temprature increases. As a result, the gas particles will be travelling faster and will collide with the walls of the container more frequently, and with more force.This means that there is a relationship between pressureand temperature. If a pressure gauge is connected to a flask of air and the flask is heated, a graph of pressure against temperature can be produced.

A physcial quality is something that can be measured. Scalar quantities have a magnitude or size.

• Tempreture 'c
• Mass kg
• Energy J
• Distance m
• Speed m/s
• Density kg/m³

Vector quantities have both magnitude and an associated direction (a.d). This makes them different from scalar quantities, which just have magnatude.

• Force 20 N to the left 
• Displacement km east 
• Velocity 11 m/s upward 
• Acceleration 9.8 m/s² downwards
• Momentum 250 kg m/s south west

The resultant force is the overall force acting on an object. This is where all the forces can be replaced by a single force that has the exact same effect as all the original forces acting together.

First law          Object rest raimain at rest and objects in motion remain in motion in a atraight line unless acted upon by an unbalaced force 

Secound law           Force equals mass times acceletion or ( f = ma )

Third law              For every action there is an equal and opposite reaction

The centre of mass of an obect is the point its weight force acts from.

For non symetrical ojects use a plum line