Arock is dropped from a height of 2.5 meters. what is it’s velocity when it reaches the ground? 3.5 meters/second

7.0 m/s

Explanation:

The question is on Free-Fall

In a free fall, an object falls freely without only gravity acting on it. Velocity at the top is zero m/s

Height of fall, h=1/2gt²

Velocity, v=gt where g is gravity acceleration=9.8m/s² and t is time taken fall the fall

Finding the t taken for the fall;

h=2.5m but we know h=1/2gt²⇒substitute values in this equation

2.5=1/2×g×t²

2.5=1/2×9.8×t²⇒2.5=4.9t²

make t subject of the equation;

t²=2.5/4.9

t=√2.5/4.9 =0.7143sec

Finding the velocity

v=gt

v=9.8×0.7143=7m/s

layer a is the exosphere and layer b is the thermosphere.   is the answer i think but i hope this .

a straight line sloped