Physical Science EOCT Review

Milton High School

Atomic number – number of protons; identifies the element Atomic mass – number of protons plus the number of neutrons in the nucleus of atom (protons + neutrons) Protons = positive charge Neutrons = no charge Electrons = negative charge You can know the number of electrons because in neutral atom the number of electrons is the same as the number of protons

If the atomic number for arsenic is 33 and the atomic mass is 75 then:

How many protons does arsenic have?

How many neutrons can you find in the nucleus of the arsenic-75?

How many electrons in arsenic’s electron cloud?

33

42

33

What is an isotope?

Isotopes = atoms with different number of neutrons

Fusion or Fission

Fusion = joining together two nuclei; example the Sun Fission = splitting apart of atoms; such as in nuclear reactor plants

Fission

Phase change – occur as a result of energy being added or taken away from matter

As temperature rises, matter moves to a more rapid state

Force = mass x acceleration

F = ma

If F = 100 N and m = 50 kg;

what is the dog’s acceleration?

100 N = 50kg (a) 100 N /50kg = a 2 m/s2 = a

Mass vs. Weight

Weight = mass x gravity

Newton’s First Law of Motion

An object at rest will remain at rest and an object in motion will remain in motion unless acted on by an outside net force; objects tend to keep doing what they are doing

Newton’s First Law of Motion

Newton’s Second Law of Motion

change of velocity, or

acceleration, is related to the mass of

the body and the force applied

Newton’s Third Law of Motion

For every action, there is an equal and opposite reaction

Work = Force x Distance

If the blonde boy does not make the rock move is he doing any work?

NO…you need distance

More Physics

• Speed = distance/time

• Velocity is speed in a particular direction

• Acceleration is change in velocity/time elapsed

Waves

Electromagnetic Spectrum

Long wavelength = low frequency Short wavelength = high frequency

Electromagnetic waves do not need to travel through a medium

Speed of Sound – depends on the medium it passes through

Sound cannot pass through a vacuum – no molecules present

Sound waves travel faster at higher temperatures and density

Sound travels faster through a solid and slower through a gas

Reflection

Angle of incidence is equal to angle of reflection

Refraction – bending of waves due to a change in speed

Diffraction- bending of waves around a barrier (all waves can be diffracted)

Interference – when two waves meet while traveling through the same medium

(a) Constructive (b) Destructive

Electricity

•Electricity – flow of electrons •Voltage – amount of energy available to move electrons •Current – rate of electron flow •Resistance – hindering electron flow

Electricity

• Voltage = current x resistance

V = IR

Electromagnets

More turns of copper wire = stronger magnetic field