Question

state universal law of gravitation explain its significance mass of an object is 20 kg find its weight on Earth and on moon

Answer 1

we know in earth

W = ma

given, m = 20kg

here acceleration (a) would be g = 10m/s²

so W = 20×10 =200kg

as we know

weight on moon = 1/6 weight on earth

so weight on moon= 200/6= 33.33kg

hope this helps

Answer 2

universal law of gravitation : Every object in the universe attracts every other object with a force which is proportional to the product of their masses and inversely proportional to the square of the distance between them. The force is along the line joining the centres of two objects .
e.g., if two masses $m_1$ and $m_2$ are given , separation between them is r
then, gravitational force act on them is $F=\frac{Gm_1m_2}{r^2}$

after solving $g=\frac{GM}{r^2}$ we get, g= 9.8 m/s² , where G is universal gravitational constant, M is mass of earth and r is the radius of earth.

so, weight of body of mass 20kg on the earth = 20 × g = 20 × 9.8 = 196N

weight of body on moon is one - sixth of weight of body on earth.
so, weight of body on moon = 196/6 = 32.66N