NAIJA EXAM RUNZ ONLINE PHYSICS TUTORIAL: MEASUREMENT AND UNITS
MEASUREMENT AND UNITS
Measurement: This is the act of knowing the actual value of an object. (Objects=Matter e.g solid, liquid & gas).
(Click here to get all 2016 Nov/Dec WAEC GCE EXPO)
MEASURING INSTRUMENTS
Any tools used in physics to know the exact measurement of matter are known as measuring instruments.
QUANTITIES AND INSTRUMENTS TO MEASURE THEM:
TO MEASURE MASS:
- Beam/ Chemical balance
- Level balance
TO MEASURE WEIGHT:
- Spring balance
- Lever balance
TO MEASURE TIME:
- Stop watch
- Sand clock
- Simple pendulum
- Heart beat
MEASUREMENT OF DISTANCE
- Metre rule
- Vernier Callipers: An instrument for measuring both the internal and external diameter of a cylinder or any shape in cylindrical form. It has two scales, one at the top called MAIN SCALE(M.S). the one below called VERNIER SCALE(V.S).
HOW TO READ VERNIER CALLIPER
In reading vernier calliper, note that the value you get from vernier scale MUST be divided by 100 always and it's in units (1,2,3,4.....10,11,12....25,26,27 e.t.c).
Main scale(M.S): It is situated at the top. To get main scale, note the zero point of v.s that's where you start reading the m.s. the last line(hole) of the m.s before the zero point of v.s is your value for m.s.
Vernier scale: It is found below. To get v.s, notice the line inside the vernier scale that joins m.s from top to down, the point is your v.s and must be divided by 100.
Vernier caliper Reading= M.s+V.s
- The Micrometre screw gauge(M.S.G): Instrument to measure the diameter of a rod or wire. It has two scales like that of Vernier caliper (M.s & V.s) situated beside each other. The one like a tail is the M.s and the head is V.s.
HOW TO READ (M.S.G)
Main Scale: This is the tail. To get m.s value, read the last hole of the m.s before it joined v.s.
Vernier scale: The head. Note the place where the two scales joined in v.s scale and divide the value by 100.
M.S.G reading = m.s+v.s.
(TO KNOW THE VALUE OF A HOLE: subtract the two consecutive no/no of holes between two scales i. e if the calliper is marked as 2!!!!!4!!!!6.
A hole = 4-2/5 or 6-4/5= 0.4.).
MASS AND WEIGHT
Mass is the quantity of matter in a body. Its unit is kilogram/gram (kg/g). It is a scalar quantity( having only magnitude no direction). It is denoted/represented by m.
Weight is the vertical force experience by mass due to gravitation. Its Unit is Newton (N) and it is a vector quantity (having both magnitude and direction). It is represented by w.
Relationship Between Mass and Weight:
Weight = Mass × Acceleration due to gravity
W=m×g
Where w= weight, m=mass, g= acceleration due to gravity=10m/s^2
Therefore, w=mg.
Worked example: Calculate the weight of an object whose mass is 10kg (g=10m/s^2)
Solution: Given that, w=?, m=10kg g=10m/s^2.
W=m×g= 10×10=100N.
Note: In physics , unit is very compulsory.
UNITS AND DIMENSION
Units are used to express physical quantities. For example, if we say the mass of a ball is 5kg, it means we have compared it with kilogram which is the unit of the physical quantity.
Dimension: We have 3 fundamental units in physics, which are, the unit of mass(kg), unit of length(metre), and unit of time(second).
The dimension of a physical quantities is the way it is related to the quantities of mass, length and time. Dimension of mass is 'M', Length is 'L' and time is 'T' generally called MLT.
(NOTE: THE DIMENSION OF ALL QUANTITIES IN METRE IS 'L').
DIMENSION ANALYSIS OF SOME PHYSICAL QUANTITIES
(1)AREA= LENGTH × BREADTH =L×B= L^2
(2)VOLUME= Area×h = L×B×H=L^3
(3)Speed =distance/time= L/T or LT^-1
(4)Velocity =displacement/time=L/T or LT^-1
(5)Acceleration =velocity/time= LT^-1/T= LT^-2
(6)Momentum = mass×vel.=M×LT^-1=MLT^-1.
(Search for more quantities to practice with.)
Worked example: At what respective values of X,Y,Z would the unit of momentum be dimensionally equivalent to M^xL^yT^z?
Solution:
Momentum= MLT^-1
therefore x=1, L=1, Z=-1.
Exercises:
At what respective value of a, b, c would the unit of Impulse be dimensionally equivalence to M^aL^bT^c?
(Ans, a=1, b=1, c=-1)
WRITTEN BY: OGUNDAPO JAMIU O.
NEXT TOPIC IS (MOTION).
PLEASE COMMENT BELOW TO RATE THIS TUTORIAL.
THANKS FOR READING. KINDLY SHARE MY BLOG ON SOCIAL MEDIA
Measurement: This is the act of knowing the actual value of an object. (Objects=Matter e.g solid, liquid & gas).
(Click here to get all 2016 Nov/Dec WAEC GCE EXPO)
MEASURING INSTRUMENTS
Any tools used in physics to know the exact measurement of matter are known as measuring instruments.
QUANTITIES AND INSTRUMENTS TO MEASURE THEM:
TO MEASURE MASS:
- Beam/ Chemical balance
- Level balance
TO MEASURE WEIGHT:
- Spring balance
- Lever balance
TO MEASURE TIME:
- Stop watch
- Sand clock
- Simple pendulum
- Heart beat
MEASUREMENT OF DISTANCE
- Metre rule
- Vernier Callipers: An instrument for measuring both the internal and external diameter of a cylinder or any shape in cylindrical form. It has two scales, one at the top called MAIN SCALE(M.S). the one below called VERNIER SCALE(V.S).
HOW TO READ VERNIER CALLIPER
In reading vernier calliper, note that the value you get from vernier scale MUST be divided by 100 always and it's in units (1,2,3,4.....10,11,12....25,26,27 e.t.c).
Main scale(M.S): It is situated at the top. To get main scale, note the zero point of v.s that's where you start reading the m.s. the last line(hole) of the m.s before the zero point of v.s is your value for m.s.
Vernier scale: It is found below. To get v.s, notice the line inside the vernier scale that joins m.s from top to down, the point is your v.s and must be divided by 100.
Vernier caliper Reading= M.s+V.s
- The Micrometre screw gauge(M.S.G): Instrument to measure the diameter of a rod or wire. It has two scales like that of Vernier caliper (M.s & V.s) situated beside each other. The one like a tail is the M.s and the head is V.s.
HOW TO READ (M.S.G)
Main Scale: This is the tail. To get m.s value, read the last hole of the m.s before it joined v.s.
Vernier scale: The head. Note the place where the two scales joined in v.s scale and divide the value by 100.
M.S.G reading = m.s+v.s.
(TO KNOW THE VALUE OF A HOLE: subtract the two consecutive no/no of holes between two scales i. e if the calliper is marked as 2!!!!!4!!!!6.
A hole = 4-2/5 or 6-4/5= 0.4.).
MASS AND WEIGHT
Mass is the quantity of matter in a body. Its unit is kilogram/gram (kg/g). It is a scalar quantity( having only magnitude no direction). It is denoted/represented by m.
Weight is the vertical force experience by mass due to gravitation. Its Unit is Newton (N) and it is a vector quantity (having both magnitude and direction). It is represented by w.
Relationship Between Mass and Weight:
Weight = Mass × Acceleration due to gravity
W=m×g
Where w= weight, m=mass, g= acceleration due to gravity=10m/s^2
Therefore, w=mg.
Worked example: Calculate the weight of an object whose mass is 10kg (g=10m/s^2)
Solution: Given that, w=?, m=10kg g=10m/s^2.
W=m×g= 10×10=100N.
Note: In physics , unit is very compulsory.
UNITS AND DIMENSION
Units are used to express physical quantities. For example, if we say the mass of a ball is 5kg, it means we have compared it with kilogram which is the unit of the physical quantity.
Dimension: We have 3 fundamental units in physics, which are, the unit of mass(kg), unit of length(metre), and unit of time(second).
The dimension of a physical quantities is the way it is related to the quantities of mass, length and time. Dimension of mass is 'M', Length is 'L' and time is 'T' generally called MLT.
(NOTE: THE DIMENSION OF ALL QUANTITIES IN METRE IS 'L').
DIMENSION ANALYSIS OF SOME PHYSICAL QUANTITIES
(1)AREA= LENGTH × BREADTH =L×B= L^2
(2)VOLUME= Area×h = L×B×H=L^3
(3)Speed =distance/time= L/T or LT^-1
(4)Velocity =displacement/time=L/T or LT^-1
(5)Acceleration =velocity/time= LT^-1/T= LT^-2
(6)Momentum = mass×vel.=M×LT^-1=MLT^-1.
(Search for more quantities to practice with.)
Worked example: At what respective values of X,Y,Z would the unit of momentum be dimensionally equivalent to M^xL^yT^z?
Solution:
Momentum= MLT^-1
therefore x=1, L=1, Z=-1.
Exercises:
At what respective value of a, b, c would the unit of Impulse be dimensionally equivalence to M^aL^bT^c?
(Ans, a=1, b=1, c=-1)
WRITTEN BY: OGUNDAPO JAMIU O.
NEXT TOPIC IS (MOTION).
PLEASE COMMENT BELOW TO RATE THIS TUTORIAL.
THANKS FOR READING. KINDLY SHARE MY BLOG ON SOCIAL MEDIA
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