Answer:
Time = 5 seconds
Distance = 50 meters
Explanation:
Constantly Accelerated Motion
When the velocity of a moving object changes at a constant rate, called acceleration, the velocity changes in same amounts in the same times. The question has a mistake when asking when the acceleration is 20 m/s. If the acceleration is constant, the only variable that can change to that value is the velocity. The equation to calculate the speed is
[tex]v_f=v_o+a.t[/tex]
And the distance s is
[tex]\displaystyle s=v_o.t+\frac{gt^2}{2}[/tex]
Given the object starts from rest, vo=0 and vf=20 m/s at [tex]a=4\ m/s^2[/tex]. We compute t
[tex]\displaystyle t=\frac{v_f-v_o}{a}=\frac{20-0}{4}[/tex]
[tex]\boxed{t=5\ sec}[/tex]
Now we compute s
[tex]\displaystyle s=0+\frac{4\times 5^2}{2}[/tex]
[tex]\boxed{s=50\ m}[/tex]
