Question

An object was dropped from the plane with 1000 km above the ground with a mass of 300 kg. Find the acceleration of the object each second until it reaches the ground.

Answer 1

Answer:

$9.8m/s^2$

Explanation:

The acceleration due to gravity on earth is $9.8m/s^2$ regardless of the mass of the object. This means, in the absence of air resistance, both a 3000 kg object and a 300 kg will accelerate at the same rate of $9.8m/s^2$ towards  earth.

The reason the acceleration due to gravity is the same for all masses is that by grace of nature, the inertial mass $m$ of the object from $F= ma$  equals the gravitational mass $m$ from $F =G \dfrac{mM}{R^2}$, resulting

$ma=G\dfrac{mM}{R^2}$

$\boxed{a=G\dfrac{M}{R^2}}$

which is the acceleration that only depends on the mass of earth and its radius, and not on the mass of the object.