I couldnt type it out so here's a picture
<u>Answer:</u>
Cannonball will be in flight before it hits the ground for 2.02 seconds
<u>Explanation:</u>
Initial height from ground = 20 meter.
We have equation of motion , 
, s is the displacement, u is the initial velocity, a is the acceleration and t is the time.
In this the velocity of body in vertical direction = 0 m/s, acceleration = 9.8 
, we need to calculate time when s = 20 meter.
Substituting
So it will take 2.02 seconds to reach ground.
T he role of oxygen in air supply is to keep all the ling beings live and healthy.
<h3>What is Oxygen?</h3>
Oxygen is the most important gas required for the living of human beings, animals, birds and the whole ecosystem.
Oxygen is fundamental for breath on the grounds that the body utilizes it to 'consume' food atoms. Creatures take in oxygen while breathing in and radiate carbon dioxide while breathing out. Oxygen makes up practically 21% of the all out gases in air, with the majority of the excess gas being physiologically latent nitrogen.
Oxygen assumes a basic part in breath, the energy-delivering science that drives the digestion systems of most living things. We people, alongside numerous different animals, need oxygen in the air we inhale to remain alive. Oxygen is created during photosynthesis by plants and many sorts of organisms.
Thus, the air supply needs oxygen on the majority.
Learn more about oxygen.
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