1
JEE Main 2023 (Online) 30th January Evening Shift
+4
-1
An object is allowed to fall from a height $R$ above the earth, where $R$ is the radius of earth. Its velocity when it strikes the earth's surface, ignoring air resistance, will be
A
$\sqrt{\frac{g R}{2}}$
B
$\sqrt{g R}$
C
$\sqrt{2 g R}$
D
$2 \sqrt{g R}$
2
JEE Main 2023 (Online) 30th January Morning Shift
+4
-1

If the gravitational field in the space is given as $$\left(-\frac{K}{r^{2}}\right)$$. Taking the reference point to be at $$\mathrm{r}=2 \mathrm{~cm}$$ with gravitational potential $$\mathrm{V}=10 \mathrm{~J} / \mathrm{kg}$$. Find the gravitational potential at $$\mathrm{r}=3 \mathrm{~cm}$$ in SI unit (Given, that $$\mathrm{K}=6 \mathrm{~Jcm} / \mathrm{kg}$$)

A
9
B
11
C
10
D
12
3
JEE Main 2023 (Online) 29th January Evening Shift
+4
-1

The time period of a satellite of earth is 24 hours. If the separation between the earth and the satellite is decreased to one fourth of the previous value, then its new time period will become.

A
12 hours
B
3 hours
C
6 hours
D
4 hours
4
JEE Main 2023 (Online) 29th January Morning Shift
+4
-1

Two particles of equal mass '$$m$$' move in a circle of radius '$$r$$' under the action of their mutual gravitational attraction. The speed of each particle will be :

A
$$\sqrt{\frac{G m}{4 r}}$$
B
$$\sqrt{\frac{G m}{2 r}}$$
C
$$\sqrt{\frac{G m}{r}}$$
D
$$\sqrt{\frac{4 G m}{r}}$$
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