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Physical Quantities, Units and Measurement - Coggle Diagram

- - - - Mass - Kilogram - kg
      - Length - meters - m
      - Time - second - s
      - Electric current - ampere - A
      - Temperature - kelvin - K
    - - 10^6 - mega - M
      - 10^3 - kilo - k
      - 10^-2 - centi - c
      - 10^-3 - milli - m
      - 10^-6 - micro - µ
  - - - To find the resultant vector given 2 vectors, we need to construct either a vector triangle or parallelogram, which is drawn to scale.
      - Method 1: Vector triangle
      - Method 2: Vector parallelogram
  - - - A. 3.2 cm centimetre 3.2 x 10^-2 = 3.2 x 10^-2
        B. 320µm micro- 320 x 10^-6 = 3.2 x 10^-4
        C. 3.2 x 10^4 kilo - 3.2 x 10^3
        D. 3.2m 3.2 x 10^0
        
        Ans: B
    - - Vector: Magnitude + direction
        
        Displacement
        
        Velocity
        
        Acceleration
      - Scalar: Magnitude
        
        Distance
        
        Speed
      - A. speed(s) / velocity(v)
        B. mass (s)/ weight(v)
        C. Acceleration(v)
        D. heat(s) form of energy
        
        Ans : C
    - - A. 100µm = 100 x 10^-6 = 1.0 x 10^-4
        B. 1.00 mm = 1.0 x 10^-3
        C. 1.0 cm = 1.0 x 10^-2
        D. 1.0 m = 1.0 x 10^0
        
        Ans: A
    - - A. gravitational potential energy(scalar - eg.heat) to bring the stone to the top of the building
        B.kinetic energy(scalar - eg.heat)
        C. Time taken for the stone to reach the ground(scalar)
        D. Velocity of the stone as it reaches the ground(vector)
        
        Ans : D
    - - A. 0.1 dm = 0.01 m
        B.10 km
        C. 100 Gm = 100 x 10^9 = 1000000000
        D. 10000 cm = 100m
        
        Ans : D
- - - - length (ℓ) to be measured
        
        ℓ > 1 m
      - Accuracy
        
        ± 0.1 cm
    - - length (ℓ) to be measured
        
        10 cm < ℓ < 1 m
      - Accuracy
        
        ± 0.1 cm
    - - length (ℓ) to be measured
        
        1 cm < ℓ < 10 cm
      - Accuracy
        
        ± 0.01 cm
      - Zero error
        
        If the zero mark on the vernier scale coincides with the zero mark on the main scale, there is no zero error
        
        If the zero mark on vernier scale is to the right of the main scale, this is a positive zero error,hence it has a positive value.
        
        If the zero mark on the vernier scale is to the left of the main scale, this is a negative zero error, hence it has a negative value. Count backwards from 10
        
        Record this error as Zero error ZE.
      - Reading the vernier calipers
        
        Read off the main scale directly on top of the zero mark of the vernier scale, Record this no as M.
        
        Look out for the place where the marking on main scale coincides with the marking on the vernier scale.Record this number V(V = 0.0x cm where x is any number from 0 to 9)
        
        The reading given by: M + V +/- ZE(in cm)
    - - length (ℓ) to be measured
        
        ℓ < 2 cm
      - Accuracy
        
        ± 0.001 cm
      - This instrument consists of a main scale( 1 mm per division), sleeve (0.5 mm per division) and rotating scale(0.01 mm per division)
      - Zero error
        
        If the datum line coincides with the zero mark on the rotating scale, there is no zero error.
        
        If the datum line is above the zero mark on the rotating scale, the zero error is positive
        
        If the datum line is below the zero mark on the rotating scale, the zero error is negative.
      - Reading the micro screw gauge
        
        The main scale reading in this case is 2.0 mm and the rotating scale reading is 37, which means 0.37 mm. As Such, the reading is 2.0 + 0.37 = 2.37 mm.
        
        Then +/- the RE
    - - This occurs due to wrong techniques of reading off measurement from measuring instruments.
      - To avoid committing such an error, always read off vertically above the mark on the measuring instrument.
  - - - A ticker-taper timer is a machine that makes a dot on paper (or a piece of ticker-tape -long strip of paper) at fixer intervals of time. This is usually 50 dots per sec, which means that the time between 2 consecutive dots in 0.02 s.
      - When the ticker-tape timer is attached to a moving object,it can be used to measure the speed of the object.
      - The speed of the ticker-tape can be caulated by measuring the length of the tape(L) and counting the no of intervals(N) between the dots.
      - average speed = distance/time = L/0.02 x N
    - - Oscillation are repeated, periodic motions of an object.
      - When the bob of a simple pendulum completes the move: C - D - C - B - C, the bob is said to have completed one oscillation.
      - Period is the time taken to complete one oscillation.
      - For a simple pendulum experiment, we would usually take the time for 20 oscillation of the pendulum and repeat the timing to get 2 readings, t1 and t2.
      - We would then take the avg of the 2 readings to find the avg time for 20 oscillations tavg = (t1 + t2)/ 2. This is to reduce the error due to human reaction time (random error).
      - To get the period of the pendulum, we have to divide the average time by 20. T = tavg / 20
      - By varying the length of the pendulum,ℓ, we find that the period of the pendulum is proportional to the square root of the pendulum(i.e the longer the length of the pendulum, the longer time it takes to complete one oscillation).
      - The period of the pendulum is inversely proportional to the gravitational filed strength,g (i.e lower g is - e.g. on the moon - the longer the period will be).
      - The period of the pendulum does not depends on its mass.
  - - - Apparatus needed
        
        Water
        
        Measuring cylinder
        
        Beaker/ Eureka can
        
        String
      - Procedure
        
        Fill the beaker/ eureka can with water to the brim. Raise the beaker so that is above the measuring cylinder(which is empty initially)
        
        Lower the irregular shaped object slowly into the beaker,using a string.
        
        Ensure that the irregularly-shaped object is totally submerged in water
        
        Water that is being displaced by the irregularly-shaped object will overflow into the measuring cylinder
        
        The volume of water in the measuring cylinder,V, is also the volume of irregularly-shaped object.