Vi = vf + ( a.t)
0 m/s (rest) = 80 m/s + (a.20s.-1)
a.20.-1= -80, we check if this is true; = 0 m/s= 80 + -80 = 0 ITS TRUE.
so a.20.-1= -80, a= 80/20 , Answers a= 4 m/s
<u>Answer</u>
3.44 m/s
<u>Explanation</u>
The motion apply the equations of Newton's law of motion. The ball is acceleration is -9.8 m/s² (acceleration due to gravity. It is negative because the ball is going against gravity, so it is decelerating).
The first equation of Newton's law of motion is;
V = U + at
Where V is the final velocity, U is the initial velocity, a is acceleration and t the time taken.
V = 25 + (-9.8 × 2.2)
= 25 - 21.56
= 3.44 m/s
Hold on lemme get the link for you
