g-force and acceleration of a rocket (1 Viewer)

[phoenix159]

Why is the graph for g-force/acceleration a curve and not linear?

See graph:

 

[skillstriker]

The acceleration of a rocket increases at an increasing rate. This can be shown by analysing the forces on astronauts. The two forces acting on an astronaut are upward thrust and the downward weight force. By Newton's Second Law, a = F/m so a = (T-mg)/m. Since 'm' is decreasing (as fuel is being used up; typically 90% of the rocket's mass is fuel), T remains constant and 'g' decreases with increasing altitude (since g = GM/r^2), the effect is that 'F' or 'T-mg' (numerator) increases and 'm' (denominator) decreases. This means that the acceleration increases at an increasing rate, which is why the graph is a curve and not linear.

 

[phoenix159]

Thanks