Answer:
After 9 seconds the object reaches ground.
Step-by-step explanation:
We equation of motion given as h = -16t²+128t+144,
We need to find in how many seconds will the object hit the ground,
That is we need to find time when h = 0
0 = -16t²+128t+144
16t²-128t-144= 0

Negative time is not possible, hence after 9 seconds the object reaches ground.
The pressure increase at the bottom of the pool after they enter the pool and float is 106.103 Pa.
<h3>What is absolute pressure?</h3>
Absolute pressure is the force that exists in a space when there is no matter present, or when there is a perfect vacuum. This absolute zero serves as the baseline for measurements in absolute pressure. The measurement of barometric pressure is the greatest illustration of an absolute referenced pressure. In order to determine absolute pressure, a complete vacuum is used. In contrast, gauge pressure is the amount of pressure that is measured in relation to atmospheric pressure, also referred to as barometric pressure.
given,
diameter = 6 m
depth = h = 1.5 m
Atmospheric pressure = P₀ = 10⁵ Pa
a) absolute pressure
P = P₀ + ρ g h
P = 10⁵ + 1000 x 10 x 1.5
P = 1.15 x 10⁵ Pa
b) When two person enters into the pool,
mass of the two person = 150 Kg
weight of water level displaced exists equal to the weight of person.




Area of pool 


Height of the water rise



P = ρ g h
P = 1000 x 10 x 0.0106
P = 106.103 Pa
To learn more about absolute pressure refer to:
brainly.com/question/17200230
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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.
they are called "cells"
hope this is the answer is what your looking for.