phsyics

• Physical quantities that can be measured include length, mass, time, electric current, thermodynamic temperature, and amount of substance
• Common units for physical quantities:

  • Length: meter (m)
  • Mass: kilogram (kg)
  • Time: second (s)
  • Electric current: ampere (A)
  • Thermodynamic temperature: kelvin (K)
  • Amount of substance: mole (mol)
• Prefixes for SI units:

  • 10^-9 = nano- (n)
  • 10^-6 = micro- (μ)
  • 10^-3 = milli- (m)
  • 10^-2 = centi- (c)
  • 10^-1 = deci- (d)
  • 10^3 = kilo- (k)
  • 10^6 = mega- (M)
  • 10^9 = giga- (G)
  • 10^12 = tera- (T)
• Diameter of an atom: 1 x 10^-10

  • Height of Mt. Everest: 8848
  • Digital calipers measure 0.001 cm or 0.01 mm
  • Digital micrometer screw gauge measures 0.0001 cm or 0.0001 mm
• Pendulum:

  • Measures time
  • Each complete to and fro motion is one oscillation
  • Period of a simple pendulum = time taken for one complete oscillation
  • T = t avg / 20
  • Period does not depend on mass of bob or angle of swing
  • Period depends on length of the string with g as constant
  • Period T = 2π sqrt(l/g)
• The mass can travel a greater distance at a greater speed, canceling each other out, so amplitude has no effect on period
• To determine the length L of the pendulum:

  1. Divide L by the acceleration due to gravity, i.e., g = 9.8 m/s²

  2. Take the square root of the value from Step 1 and multiply it by
• Speed:

  • Distance/time (constant)
  • Average speed = total distance traveled / total time taken
  • Velocity = displacement/time taken
  • Stationary when speed is 0
• Acceleration:

  • vf - vi / tf - ti
  • Velocity changes by how fast/slow
  • Gradient = rate of change of velocity
• Vector quantities:

  • Displacement, velocity, acceleration, force, weight
  • Have both magnitude and direction
• Scalar quantities:

  • Distance, speed, mass, energy, time
  • Only have magnitude
• Distance-time graph:

  • Gradient = speed
• Speed-time graph:

  • Gradient = acceleration
• When describing the velocity of an object, its magnitude and direction should be specified
• Two objects that have the same speed could have different velocities because their directions of motion could be different
• Acceleration may be uniform or non-uniform:

  • Uniform acceleration: change in velocity occurs at a constant rate
  • Non-uniform acceleration: change in velocity does not occur at a constant rate
• Free fall motion:

  • Under the influence of only gravitational force
  • No air resistance
• Acceleration due to gravitational force: g = 10m/s²
• For an object experiencing uniform acceleration, the change in velocity is occurring at a constant rate
• For an object experiencing non-uniform acceleration:

  • If the change in velocity occurs at an increasing rate, it is experiencing increasing acceleration
  • If the change in velocity occurs at a decreasing rate, it is experiencing decreasing acceleration
• Maximum height in free fall = maximum displacement
• Distance is the area under the speed-time graph
• Gradient of velocity-time graph = constant acceleration due to gravity
• From t= to t=, the object is moving at a constant acceleration of _m/s
• A straight line on a graph indicates constant acceleration