Answer:
a = 2 m/s²
v₄ = 8 m/s
Explanation:
We can find the final speed at the end of eight second by using first equation of motion:
[tex]v_{f} = v_{i} + at\\[/tex]
where,
vf = final velocity at 8th second = 16 m/s
vi = initial velocity = 0 m/s
a = acceleration = ?
t = time = 8 s
Therefore, using the values in the equation we get:
[tex]16\ m/s = 0\ m/s + a(8\ s)\\\\a = \frac{(16\ m/s)}{8\ s}[/tex]
a = 2 m/s²
Now, we can apply same equation of motion for 4 seconds of motion to find the velocity at the end of 4th second (v₄):
[tex]v_{4} = 0\ m/s + (2\ m/s^2)(4\ s)\\[/tex]
v₄ = 8 m/s
