Physics summer exam :(

• Air resistance

  The force on an object moving through the air that causes it to slow down (also known as drag).
• what do forces do ?

  they push or pull an object and can change their shape , speed or slow them down and change their direction
• what are forces measured in ?

  newtons
• balanced (forces)

  Forces acting on an object that are the same size but act in opposite directions.
• name the contact forces

  Friction , upthrust , air resistance , tension in string and reaction force
• name the non contact forces

  Magnetic , electrostatic , weight
• compression

  Force squashing or pushing together, which changes the shape of an object.
• contact force

  Force that acts by direct contact, e.g friction.
• deformation

  Changing shape due to a force.
• describe an interactive pair

   two forces that act in opposite directions, have equal magnitudes and act on different objects.
• when balanced forces act , what state are the objects

  stationary or moving at constant speed
• what happens when unbalanced forces act

  the objects slows down or speeds up
• Densitity

  The mass per unit volume in (g/cm3) or (kg/m3)
• how to calculate a resultant force

  you subtract the smaller force from the larger force
• what is the difference between mass and weight

  Mass is how much matter the object is made up and it stays the same Weight of an object is the force pulling down due to gravity , can change on other planets
• how does gravity vary with mass and weight

  The mass will always stay the same but the weight can vary depending on how much gravity acts upon the object
• what is the equation for weight

  mass x gravitational field strength

  (W = m x g)
• Drag

  Air resistance or water resistance or in a fluid.
• how do forces deform objects

  The force may change the object by bending , stretching or compressing
• Use Hookes Law to explain and predict the extension of a spring when force is applied

  The extension of an object is directly proportional to the force applied , therefore if the force doubles then the extension will also double
• Driving force

  The force that is pushing or pulling something.
• Explain linear and directly proportional relationships

  statistical term used to describe a straight-line relationship between two variables , increase and decrease together
• why do objects float and sink

  an object that has a higher density than the liquid will sink and an object with a lower density will float
• equilibruim

  state of an object when all forces are balance.
• what is the equation for density

  mass / volume with the units kg/m3 or g/cm3
• extension

  the difference between the original length of an object and the length when you apply a force.
• float

  an object that is less dense than its surrounding rises to the surface.
• what is the method to find the density of regular and irregular objects

  density of regular is mass / volume , density of irregular , find mass then use displacement method to find volume by finding difference between initial volume and volume when object is submerged , then mass / volume
• field 


  The region where other objects feel a gravitational force.
• state the equation to calculate pressure

  force / area
• how does increasing and decreasing area affect pressure

  if you increase area the pressure lowers and if you decrease area pressure increases because pressure = force / area , while force is the same
• Friction


  A contact force opposing motion which is caused by surfaces moving one over another.
• how does increasing and decreasing force affect pressure

  if the area remains constant but the force increases pressure
• gravitational field strength

  The force from gravity on 1 kg (N/kg). On Earth, strength of gravity is g = 10N/kg
• Gravitational force

  A non-contact force that acts between two masses.
• describe the motion of the earth and moon around the sun


  The earth orbits the sun in a counterclockwise direction and an elliptical shape which takes 365.25 days and the moon orbits around the earth simultaneously, taking 27 days.
• star


  A luminous body of hot gas ( hydrogen and helium ) held together by self gravity
• planet


  A celestial body that orbits around the sun which is not a star nor its remnants
• moon


  A natural satellite of a planet , visible by reflected light of the sun
• linear relationship


  When two variables are graphed and show a straight line. If it goes through the origin, and they can be called directly proportional.