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Mass: It is the amount of matter (substance) in a body.
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Weight: The downward force equal to product of mass and the gravitational field strength.
W = m g
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Differences:
|
Weight |
Mass |
|---|---|
|
It is a force. |
It is the amount of matter in a body. |
|
Measured in N |
Measured in kg |
|
Vector |
Scalar (,i.e., no direction) |
|
Changes from place to place |
Constant regardless of location |
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Inertia: It is the reluctance of mass to a change in its state of motion.
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A truck has more mass and hence more inertia than a car.
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Gravitational field strength of Earth is 10 N/kg. This means that the strength of Earth’s gravity is so strong that an object will have a weight of 10 N for every kg of mass that it has.
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Unit: N/kg
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Measuring instruments:
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Spring balance: Measures weight.
Using the formula W=mg, it can have a scale for mass too. The value of ‘g’ is assumed in such a case.
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Beam balance: Measures mass by comparing the weight of a mass with the weight of known masses (e.g., discs).
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Density: It is the mass per unit volume.
ρ = m / V
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SI Unit: kg/m3
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Measurement of volume: Volume can be found by:
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Displacing a liquid
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For regular shaped objects such as a block or cylinder, a formula may be used.
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Less dense liquids and gases rise above more dense liquids and gases respectively.
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