Answer :
Answer:
[tex]\bar{v}=20\ m/s[/tex]
Explanation:
Constant Acceleration Motion
It's a type of motion in which the velocity changes by an equal amount in every equal period of time.
If vo is the initial speed, vf the final speed, and t the time, the acceleration is calculated as follows:
[tex]\displaystyle a=\frac{v_f-v_o}{t}[/tex]
The final speed is calculated by solving the above equation:
[tex]v_f=v_o+at[/tex]
The object starts from rest (v0=0) with a constant acceleration of a= 8 m/s^2 during t=5 seconds. Thus the final speed is:
[tex]v_f=0+8 m/s^2\cdot 5\ s[/tex]
[tex]v_f=40\ m/s[/tex]
The average velocity (speed in this case) is
[tex]\displaystyle \bar{v}=\frac{v_o+v_f}{2}[/tex]
[tex]\displaystyle \bar{v}=\frac{0+40}{2}[/tex]
[tex]\boxed{\bar{v}=20\ m/s}[/tex]
Note: The average speed could also be calculated as the distance traveled x by the time. It would lead to identical results.