JEE PHYSICS MCQ: GRAVITATION

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Assertion: Two blocks of masses

m_1

and

m_2

are at rest. They are moving towards each other under the mutual internal force. The velocity of centre of mass is zero.

Reason: There is no effect of external forces on the motion of centre of mass.

View answer and explanation

Correct option: B

If both assertion and reason are true but reason is not correct explanation of the assertion.

Option B is correct because both the assertion and the reason are true, but the reason (no external forces) doesn't directly explain why the center of mass velocity is zero in this specific scenario.

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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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