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Why is the weight of an object at a high altitude less than its weight at the sea level?

Explanation

The weight will be less at the place where the gravitational force is less. as the object rises to higher altitude, it is moving away from the centre of the earth. The gravitational force at the higher altitudes will be lesser as compared to that of at the sea level therefore weight of an object at a high altitude less than its weight at the sea level.