JEE PHYSICS MCQ: GRAVITATION

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Assertion: A particle is projected upwards with speed

v

and it goes to a height

h

. If we double the speed then it will move to height

4 h

.

Reason: In case of earth, acceleration due to gravity

g

varies as

g \propto \frac{1}{r^2}

(for

r \geq R

)

View answer and explanation

Correct option: D

If Assertion is false but the Reason is true

Option D is correct. The Assertion is false because the height reached is proportional to the square of the initial velocity only if 'g' is constant. The Reason is true because acceleration due to gravity varies inversely with the square of the distance from the Earth's center.

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The escape velocity for a body projected vertically upwards from the surface of the earth is

11.2\mathrm{\;\;km}{\mathrm{s}^{ - 1}}

. If the body is projected in a direction making an angle of

{45^0}

with the vertical, the escape velocity will be The escape velocity of a body projected from the surface of earth is

v_e

. If the body is projected at an angle

\theta

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