Answer:acceleration=2.5m/s^2
Explanation:
initial velocity(u)=0
Distance(d)=20m
Time(t)=4seconds
Acceleration=a
D=uxt+(axt^2)/2
20=0+(ax4^2)/2
20=(ax4x4)/2
20=16a/2
Cross multiplying we get
20x2=16a
40=16a
Divide both sides by 16
40/16=16a/16
2.5=a
Acceleration=2.5m/s^2