Answer:
0.25 N
Explanation:
The density of the ball (
) = 0.0839 g/cm³ = 83.9 kg/m³
The density of water (
) = 1000 kg/m³
diameter = 3.77 cm = 0.0377 m
radius of ball = 0.0377/2 = 0.01885 m
The volume (V) = 
Let us assume the acceleration due to gravity (g) = 9.8 m/s²
Hence:
The force is required to hold it completely submerged under water (F) is:

F = 0.25 N
Answer:
Explanation:
Resistivity and resistance are proportional and depends of the length and the cross-sectional area of the wire:

furthermore, the density is the mass divided by the volume, and the volume can be written as the area multiplyed by the length:

Now you have tw equations and two variables, so you can solve for each of them.
first, solve for A in both equations and replace them:


now replace this into any of the previous equiations:

If you assume the wire has circular cross-sectional area, then the area is:

solving for d:

replacing A and simplifying:
![d=2 \sqrt[4]{\frac{m\rho}{\rho_m R \pi^2} }](https://tex.z-dn.net/?f=d%3D2%20%5Csqrt%5B4%5D%7B%5Cfrac%7Bm%5Crho%7D%7B%5Crho_m%20R%20%5Cpi%5E2%7D%20%7D)
Because the air gets stuck in the curves of the frissbee
Edit: You do mean Ridge?
Rocks near Mid-Ocean Ridge are younger than rocks near the trenches.
Seismic data shows oceanic crust is sinking into the mantle at the trenches.
Matching bands of magnetic rock are found on either side of the Ridge. Earth's magnetic fields change these bands over time.