P2.1 MOTION

• how to calculate speed?

  distance / time
• equipment to measure distance?

  tape measure or trundle wheel
• equipment to measure time?

  stopwatch or timer
• unit for mass

  kilograms, kg
• unit for length

  metre, m
• unit for time

  seconds, s
• unit for current

  ampere, a
• unit for temperature

  kelvin, k
• unit for frequency

  hertz, Hz
• unit for force

  newtons, n
• unit for energy

  joule, j
• unit for power

  watts, w
• unit for pressure

  pascals, pa
• unit for electrical charge

  coulomb, c
• unit for potential difference

  volts, v
• unit for electrical resistance

  ohm
• Scalars

  • Scalars are quantities that have only a magnitude
  • For example, mass is a scalar since it is a quantity that has magnitude without a direction
  • Distance is also a scalar since it only contains a magnitude, not a direction
• Vectors

  • Vectors have both magnitude and direction
  • Velocity, for instance, is a vector since it is described with both a magnitude and a direction
  • When describing the velocity of a car it is necessary to mention both its speed and the direction in which it is travelling
• This graph shows how the slope of a line is used to interpret the speed of moving objects. Both of these objects are moving with a constant speed, because the lines are straight.

  A) larger

  B) smaller

  
• acceleration = change in velocity / time
• change in velocity = final velocity - initial velocity
• (final speed)2 − (initial speed)2 = 2 × acceleration × distance travelled
• kinetic energy


  The energy an object has as a result of its mass and speed