Question

what is the weight of a 70 kg body on the surface of a Planet whose mass is one seventh that of earth and radius is half of Earth​

Answer 1

Answer:

The Weight of the body will be 40.07 kgf.

Explanation:

Mass of the body = 70 kg

Earth's mass = 5.96*10²⁴ kg

Earth's radius = 6.37*10⁶ m

Let the Planet be "Planet x".

Planet x's Mass = [5.96*10²⁴] / 7 kg

= 8.51*10²³  kg

Planet x's Radius = [6.37*10⁶] / 2 m

= 3185000 m

Or,

= 3.18*10⁶ m

Value of G = 6.67*10⁻¹¹ N.m²/kg²

Gravitational Force on Planet x = [Gm] / r²

= [ {6.67*10⁻¹¹} * {8.51*10²³} ] / [3.18*10⁶]²  

= [ {6.67*8.51} * 10⁻¹¹⁺²³} / 1.011*10¹³

= [ 56.76*10¹² ] / 1.011*10¹³

= [ 56.76/1.011 ] * 10¹²⁻¹³

= 56.14*10⁻¹ m/s²

= 5.61 m/s²

Force = Mass*Gravitational Force

Weight=Force

= [70*5.61] N

= 392.7 N

1 kgf = 9.8 N

392.7 N = [392.7/9.8] kgf

= 40.07 kgf

Hope this helps.