A BODY WEIGHS 72 N ON THE SURFACE OF THE EARTH. WHAT IS THE GRAVITATIONAL FORCE ON IT, AT A HEIGHT EQUAL TO HALF THE RADIUS OF THE EARTH?

 [NEET - 2020]

(a) 48 N (b) 32 N (c) 30 N 4) 24 N

PHYSICS_WITH_AKSHAY_GOLE



Gravitational acceleration at height  ‘h’ is

\[g_{h}=g\left ( 1+\frac{h}{R} \right )^{-2}\]

Multiplying both side by 'm' we get,
\[mg_{h}=mg\left ( 1+\frac{h}{R} \right )^{-2}\]
\[W_{h}=W\left ( 1+\frac{h}{R} \right )^{-2}\]

As, h=R/2,

\[W_{h}=W\left ( 1+\frac{\frac{R}{2}}{R} \right )^{-2}\]
\[W_{h}=W\left ( 1+\frac{1}{2} \right )^{-2}\]
\[W_{h}=W\left ( \frac{3}{2} \right )^{-2}\]
\[W_{h}=W\left ( \frac{2}{3} \right )^{2}\]
\[W_{h}=72*\left ( \frac{4}{9} \right )\]

Therefore, The gravitational force on body at a height equal to half the radius of earth is 
\[W_{h}=32 N\]


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Milan Tomic

Hi. I’m Designer of Blog Magic. I’m CEO/Founder of ThemeXpose. I’m Creative Art Director, Web Designer, UI/UX Designer, Interaction Designer, Industrial Designer, Web Developer, Business Enthusiast, StartUp Enthusiast, Speaker, Writer and Photographer. Inspired to make things looks better.

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