Aball is thrown vertically upward with a velocity of 20m/s. what is the maximum height after 30secs

Maximum height: 20.4 m, height at 30 s: -274 m

Explanation:

If you want to find the height of the ball after 30 seconds, we must use the equation:

where

u = 20 m/s is the initial velocity

a = g = -9.8 m/s^2 is the acceleration of gravity

t is the time

Substituting t = 30 s,

This means that the ball is 274 m below its original level.

If you want to find the maximum height, then it can be find by using the law of conservation of energy: in fact, at the maximum height, all the initial kinetic energy  has been converted into potential energy, so

And solving for h, we find the maximum height:

in simple terms, the principle states that the buoyancy force on an object is equal to the weight of the fluid displaced by the object, or the density of the fluid multiplied by the submerged volume times the gravitational acceleration, g. this is also known as upthrust.