Answer:
a. t = 2 s
b. vf = 20 m/s
Explanation:
a.
We can the second equation of motion to find out the time to reach the ground:
[tex]h = v_it + \frac{1}{2}at^2[/tex]
where,
h = height = 20 m
vi = initial velocity = 0 m/s
t = time taken to reach the ground = ?
a = acceleration = 10 m/s²
Therefore,
[tex]20\ m = (0\ m/s)t+\frac{1}{2} (10\ m/s^2)t^2\\\\t^2 = \frac{20\ m}{5\ m/s^2}\\\\t = \sqrt{4\ s^2}[/tex]
t = 2 s
b.
Here, we will use the first equation of motion to find the final speed:
[tex]v_f = v_i + at\\v_f = 0\ m/s + (10\ m/s^2)(2\ s)[/tex]
vf = 20 m/s
