Question

How does jumping into a pool change the amount of gravity acting on you?​

Answer 1

Answer:

Because of the buoyant force

Explanation:

Jumping into a pool change the amount of apparent gravity acting on a person.

Normally, for a person in free fall, the weight of the person is given by:

$F=mg$

where m is the mass of the person and g=9.8 m/s^ is the acceleration due to gravity.

When a person is in the water, there is a buoyant force pushing the person upward. The magnitude of the buoyant force is

$B=\rho_w V g$

where

$\rho_w$ is the density of the water

V is the volume of displaced fluid

g is the acceleration due to gravity

So the net force acting on the person is

$F= mg - \rho_w V g$ (1)

Since V corresponds to the volume of the person, we can rewrite it as

$V=\frac{m}{\rho_p}$

where $\rho_p$ is the density of the person. Substituting into eq.(1),

$F=mg- m \frac{\rho_w}{\rho_p} g = mg - mg'$ (2)

where we called

$g'=\frac{\rho_w}{\rho_p} g$

So we can further rewrite (2) as

$F=m(g-g')$

so we see that the gravity acting on the person, g, has been modified into (g-g') due to the presence of the buoyant force.