Gravitation

Question 1

Kepler’s 3 laws

Answer 1

Law of orbits: all planets move in elliptical orbits with sun at 1 of the foci
Law of areas: line joining any planet to sun sweeps equal areas in equal intervals of time.
Law of periods: Sq of the period of revolution of planet is directly prop to cube of semi major axis of the eclipse traced out by the planet

Question 2

Universal law of gravitation

Answer 2

Every body attracts every other body with a force directly proportional to product of their masses and inversely to Sq of distance btw them

Question 3

Value of G

Answer 3

6.67 × 10^-11 Nm²/kg²

Question 4

When mass is on earth surface, g =

Answer 4

G(Me)/R(e)²

Question 5

g at height h is

Answer 5

g(h) = G(Me)/[R(e)+h]²

Question 6

If h«R(e) g=

Answer 6

g(h) = g[1 - 2h/R(e)]

Question 7

If small depth d g(d) =

Answer 7

g[1 - d/R(e)]

Question 8

Escape speed + formual

Answer 8

Min speed for the obj to reach infinity
V(e) = [2gR(e)]½

Question 9

Value of V(e)

Answer 9

11.2 km/s

Question 10

Radius of earth

Answer 10

6400km