Answer the following:
(a) You can shield a charge from electrical forces by putting it inside a hollow conductor. Can you shield a body from gravitational influence of nearby matter by putting it inside a hollow sphere or by some other means ?
(b) An astronaut inside a small spaceship orbiting around the earth cannot detect gravity. If the space station orbiting around the earth has a large size can he hope to detect gravity ?
© If you compare the gravitational force on the earth due to the sun to that due to the moon, you would find that the sun’s pull is greater than moon’s pull. However, the tidal effect of the moon’s pull is greater than the tidal effect of the sun. Why ?
(a) No. Electrical forces depend upon the nature of the intervening medium while the gravitational forces don’t depend upon the nature of the intervening medium. So, such shielding acts are not possible in case of gravitation i.e., gravity screens are not possible.
(b) Yes, Astronaut can hope to detect gravity if the size of th e spaceship is extremely large, then the magnitude of the gravity will become appreciable and hence the gravitational effect of the spaceship may been me measurable.
© Earth moon distance is very small as compared to earth-sun distance. Tidal effect is inversely proportional to the cube of the distance it means it is not governed by inverse square law like the gravitational force (which obeys inverse square law). Hence, tidal effect of moon is larger than that due to the sun.