Suppose a body possesses a large mass and a large weight and this body is a very large object that is hard to throw because of its weight.
Therefore by using Newton’s second law which states that the magnitude of the acceleration is ‘g’ for an object which is freely falling.
Therefore, if the mass of an object is 1 kg which is falling with an acceleration of 9.8 ms⁻², the magnitude of the force will be given by-
F = ma
F =(1 kg) x (9.8 ms⁻²)
F = (9.8 kg.ms⁻²)
F = 9.8 N
Hence, it is clear that for an object with mass m= 1 kg, the weight of the object will be equal to 9.8 N.
Examples:
Question: For a freely falling object of mass 10Kg, an upward force of 20N is applied. Find the final acceleration. ( g=10m/s2�=10m/s2 )
Ans:
Net downward force = weight of the object = 100 N
Net upward force = 20N
Net force = 80N in the downward direction.
So, Net acceleration =
80108010 = 8Kg
Question: What will be the weight of an object on the moon, if its weight is 90N on earth.
Ans: Weight of an object on earth = 90N
Weight of object on moon =?
We know that gravitational force on the moon is equal to one-sixth of earth’s gravitational force.
Weight of a body on earth,
Wearth�����ℎ =
mgearth������ℎ
Weight of a body on the moon,
Wmoon����� =
mgmoon������ ==
mgearth6������ℎ6 =
Wearth6�����ℎ6 =
906906 = 15N
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