JEE Main 2020 (Online) 6th September Evening Slot | Gravitation Question 82 | Physics

JEE Main 2020 (Online) 6th September Evening Slot

MCQ (Single Correct Answer)

-1

Two planets have masses M and 16 M and their radii are $$a$$ and 2$$a$$, respectively. The separation between the centres of the planets is 10$$a$$. A body of mass m is fired from the surface of the larger planet towards the smaller planet along the line joining their centres. For the body to be able to reach at the surface of smaller planet, the minimum firing speed needed is :

$$2\sqrt {{{GM} \over a}} $$

$$\sqrt {{{G{M^2}} \over {ma}}} $$

$${3 \over 2}\sqrt {{{5GM} \over a}} $$

$$4\sqrt {{{GM} \over a}} $$

JEE Main 2020 (Online) 5th September Evening Slot

MCQ (Single Correct Answer)

-1

The acceleration due to gravity on the earth’s surface at the poles is g and angular velocity of the earth about the axis passing through the pole is $$\omega $$. An object is weighed at the equator and at a height h above the poles by using a spring balance. If the weights are found to be same, then h is (h << R, where R is the radius of the earth)

$${{{R^2}{\omega ^2}} \over {2g}}$$

$${{{R^2}{\omega ^2}} \over g}$$

$${{{R^2}{\omega ^2}} \over {8g}}$$

$${{{R^2}{\omega ^2}} \over {4g}}$$

JEE Main 2020 (Online) 5th September Morning Slot

MCQ (Single Correct Answer)

-1

The value of the acceleration due to gravity is g₁ at a height h = $${R \over 2}$$ (R = radius of the earth) from the surface of the earth. It is again equal to g₁ at a depth d below the surface of the earth. The ratio $$\left( {{d \over R}} \right)$$ equals :

$${5 \over 9}$$

$${1 \over 9}$$

$${7 \over 9}$$

$${4 \over 9}$$

JEE Main 2020 (Online) 4th September Evening Slot

MCQ (Single Correct Answer)

-1

A body is moving in a low circular orbit about a planet of mass M and radius R. The radius of the orbit can be taken to be R itself. Then the ratio of the speed of this body in the orbit to the escape velocity from the planet is:

$$\sqrt 2 $$

$${1 \over {\sqrt 2 }}$$

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