Assertion : two bodies of masses M and m (M > m) are allowed to fall from same height if air resi

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2.Motion in Straight Line

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$Assertion$ : The two bodies of masses $M$ and $m$ $(M > m)$ are allowed to fall from the same height if the air resistance for each be the same then both the bodies will reach the earth simultaneously.

$Reason$ : For same air resistance, acceleration of both the bodies will be same

A

If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

B

If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

C

If the Assertion is correct but Reason is incorrect.

D

If both the Assertion and Reason are incorrect.

(AIIMS-2014)

Solution

The force acting on the body of mass $M$ are its weight $Mg$ acting vertically downward and air resistance $F$ acting vertically upward.

$\therefore $ Acceration of the body, $a = g – \frac{F}{M}$ Now $M > m$,

therefore, the body with larger mass will have great acceleration and it will reach the ground first.

Standard 11

Physics

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