Kinematics

Class Summary:

Scalar: A quantity with a magnitude but no direction. Eg. 20 meters

Vector: A quantity with magnitude and direction. Eg. 20 meters West

Distance: How far an object has traveled in total.

Displacement: How far an object is from its starting point.

Speed: The rate at which an object is moving.

Velocity: The rate at which an objects is moving in a given direction.

Significant Figures:

• Don’t round until the end!!!
• Trailing zeros count after a decimal (eg. 1.00 has 3 sig figs)
• Trailing zeros do NOT count if there is no decimal (eg. 5000 has 1 sig figs)
• Leading zeros do NOT count after a decimal (eg. 0.0053 has 2 sig figs)
• When adding/subtracting keep the smallest decimal place
  • Eg. 20.225 + 1.2 = 21.4
• When multiplying/dividing, keep the least sig figs
  • Eg. 12 * 0.25003 = 3.0

Uncertainty:

• Half the smallest value you can see, unless the device says otherwise (such as a scale)
• When two values are added/subtracted, add the uncertainties.
  • Eg. 10cm +/- 0.5cm + 12cm +/- 0.1cm = 22cm +/- 0.6cm
• When two values are multiplied/divided , convert the errors to % and then add them. You can convert them back afterwards.
  • Eg. 10cm +/- 5% x 12cm +/- 0.83% = 120cm +/- 5.83% = 120cm +/- 7cm