Question:

The weight of a body at the surface of earth is $18\, N$ The weight of the body at an altitude of $3200 \,km$ above the earth's surface is (given, radius of earth $R _{ e }=6400 \,km$ ):

Updated On: Oct 18, 2024
  • 19.6 N
  • 9.8 N
  • 4.9 N
  • 8 N
Hide Solution
collegedunia
Verified By Collegedunia

The Correct Option is D

Solution and Explanation

Acceleration due to gravity at height \(h\) 
\(g'=\frac{g}{[1+\frac{h}{R}]^2}\) 

So weight at given height 

\(mg'=\frac{mg}{[1+\frac{h}{R}]^2}\)

=\(\frac{18}{[1+\frac{1}{2}]^2}=8N\)

\(\text{Therefore, the correct option is (D):} 8N\)

Was this answer helpful?
10
2

Concepts Used:

Gravitation

In mechanics, the universal force of attraction acting between all matter is known as Gravity, also called gravitation, . It is the weakest known force in nature.

Newton’s Law of Gravitation

According to Newton’s law of gravitation, “Every particle in the universe attracts every other particle with a force whose magnitude is,

  • F ∝ (M1M2) . . . . (1)
  • (F ∝ 1/r2) . . . . (2)

On combining equations (1) and (2) we get,

F ∝ M1M2/r2

F = G × [M1M2]/r2 . . . . (7)

Or, f(r) = GM1M2/r2

The dimension formula of G is [M-1L3T-2].