Question

What is value of ''G" and derive its unit?

Answer 1

Answer:

we know, according to Newton's gravitational law ,

F=\frac{GMm}{r^2}F=

r

2

GMm

here F is force experienced by object m due to earth gravitational field. it is also known as gravitational force. it is equal to weight of body .so , F = mg

hence, mg=\frac{GMm}{r^2}mg=

r

2

GMm

g=\frac{GM}{r^2}g=

r

2

GM

here, G is gravitational constant

M is the mass of earth ,

r is the radius of earth.

so, G=6.67\times10^{-11}Nm^2/Kg^2G=6.67×10

−11

Nm

2

/Kg

2

M=5.972\times10^{24}KgM=5.972×10

24

Kg

r=6.4\times10^6mr=6.4×10

6

m

after putting it we get, g = 9.8 m/s²