# Physics help pleasee asap?

Standing on planet v that has a radius of 2*10^5.

5kg of my food has been release from rest at a height of 4m

it takes 4s to reach the surface

what will the gravitational acceleration of my food be while falling?

what is the mass of the planet?

### 3 Answers

- NCSLv 71 month ago
a) from h = ½gt²

we get

g = 2h / t² = 2*4m / (4s)² = 0.5 m/s²

b) Newton's Law of Gravitation:

g = GM / r²

so

0.5 m/s² = 6.674e−11N·m²/kg² * M / (2E5m)²

means that

mass M = 3E20 kg

as long as the units on your radius was "meters."

If the units are "kilometers," then M = 3E26 kg.

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- 1 month ago
1) for the planet acceleration due to gravity is

g = 2h / t’2 = 2x4 / 16 = 0.5 m/sec’2

2) mass of the planet M = g R’2 / G = 0.5 x 4x10’10 / 6.67x10’-11 = 3x10’20 kg.

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- oubaasLv 71 month ago
2h = g*t^2

g = 2h/t^2 = 8/4^2 = 0.5 m/sec^2 = M*G/r^2

M = 0.5*4*10^10*10^11/6.674 = 3.00*10^20 kg

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