1
JEE Main 2017 (Online) 9th April Morning Slot
+4
-1
The mass density of a spherical body is given by
$$\rho$$ (r) = $${k \over r}$$ for r $$\le$$ R and $$\rho$$ (r) = 0 for r > R,

where r is the distance from the centre.

The correct graph that describes qualitatively the acceleration, a, of a test particle as a function of r is :
A
B
C
D
2
JEE Main 2017 (Online) 8th April Morning Slot
+4
-1
If the Earth has no rotational motion, the weight of a person on the equator is W. Determine the speed with which the earth would have to rotate about its axis so that the person at the equator will weigh $${3 \over 4}$$ W. Radius of the Earth is 6400 km and g=10 m/s2.
A
1.1 $$\times$$ 10−3 rad/s
B
0.83 $$\times$$ 10−3 rad/s
C
0.63 $$\times$$ 10−3 rad/s
D
0.28 $$\times$$ 10−3 rad/s
3
JEE Main 2017 (Offline)
+4
-1
The variation of acceleration due to gravity $$g$$ with distance d from centre of the earth is best represented by (R = Earth’s radius):
A
B
C
D
4
JEE Main 2016 (Online) 10th April Morning Slot
+4
-1
An astronaut of mass m is working on a satellite orbiting the earth at a distance h from the earth’s surface. The radius of the earth is R, while its mass is M. The gravitational pull FG on the astronaut is :
A
Zero since astronaut feels weightless
B
0 < FG < $${{GMm} \over {{R^2}}}$$
C
$${{GMm} \over {{{\left( {R + h} \right)}^2}}}$$ < FG < $${{GMm} \over {{R^2}}}$$
D
FG = $${{GMm} \over {{{\left( {R + h} \right)}^2}}}$$
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