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प्रश्न
A body falls freely under gravity from rest and reaches the ground in time t. Write the expression for the height fallen by the body.
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उत्तर
Initial velocity, u = 0.
Time taken = t.
Acceleration due to gravity = g.
Let 'h' be the height fallen.
`"h" = "ut" + 1/2 "gt"^2`
`"h" = 1/2 "gt"^2`
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1) Complete the following statement by choosing the right option.
The stone held in the hand is stable because on it __.
- two unbalanced forces are exerted.
- only the gravitational force of the earth is exerted.
- gravitational force of the earth is not exerted.
- two balanced forces are exerted.
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5) Why does free fall happen only in a vacuum?
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