physic

• density = mass over volume, unit = kg/m^3
• force = pressure x surface area, unit = N (Newton)
• distance = speed times time, unit = metres per second
• velocity = distance divided by time, unit = m/s
• acceleration = change in velocity divided by time, unit = m/s^2
• pressure = force(weight) divided by area, unit = Pa
• weight = mass over gravitational field, unit = N/kg
• smaller the area of contact, the larger the pressure
• larger the area contact, the smaller the pressure exerted
• larger the force applied, the larger pressure exerted
• smaller the force applied, the smaller the pressure exerted
• density of material > density of water = sink
• density of material < density of water = float
• mass= measured with beam / electronic balance
• weight = measured with spring balance
• gravitational field strength- earth = 10N/kg, moon = 1.6N/kg
• gravitational field= region in which a mass experience force due to gravitational attraction
• force is a push and pull (not an energy)
• contact force = exist when objects are in contact
• non-contact force = forces do not need objects to be on contact
• mass

  • not a force
  • measure the amount of matter (atoms, molecules, compounds) in a body
  • does not change regardless of location or shape
  • SI UNITS : kg
  • scalar quantity
• weight

  • gravitational force acting on an object that has mass
  • SI UNITS : N --> newton
  • direction --> downwards, towards centre of the earth
  • vector quantity
• earth´s gravitational field strength = 10N/kg

  moon´s gravitational field strength = 1.6N/kg (5x slower)
• formula for mass and weight

  g=weight/ mass
• • density formula

  density = mass/volume

  • SI UNIT

  kg/m^3