physics

• si unit for length is metre
• The SI unit of force is the newton (N).
• A force can be calculated using F = ma, where m is mass and a is acceleration.
• si unit for mass is kg
• SI unit for time is second
• SI unit for current is ampere
• SI unit for temperature is kelvin
• SI unit for electric charge is coulomb
• period of oscillation refers to the time taken to move from a to b and back to a
• frequency

  number of oscillations per second
• scalar quantity

  only has magnitude but no direction
• examples of scalar quantity

  speed, distance, mass
• vector quantity


  has both magnitude and direction
• examples of vector quantity

  velocity, displacement, acceleration
• suitable instrument of diameter of thin wire

  micrometer screw guage
• suitable instrument of mass of a stone

  electronic balance
• average speed = distance / time taken
• acceleration = final velocity - initial velocity / time
• mass

  amount of matter in a body, scalar quantity, measured by electronic balance
• mass is not a force
• weight is the amount of force acting on a body
• weight is a vector quantity
• weight is measured by a spring balance
• weight is measured in newton
• weight = (mass)(gravitational field strength)
• weight varies depending on gravitational field strength (increase of decrease)
• gravitational field strength will always be 10N/KG
• mass is constant (remains unchanged) depending on gravitational field strength
• density of a substance is mass per unit volume
• density = mass/volume
• density is kg/m3
• lower density = floats
• higher density = sinks
• if density is higher than water, it sinks
• pressure is force/area
• si unit of pressure is pa
• smaller the contact, pressure is larger
• balanced forces

  both forces are equal in magnitude but opposite in direction
• in balanced forces

  resultant force is 0N
• balanced forces

  acceleration = 0. velocity remains the same