Answer:
See the answers below
Explanation:
To solve this problem we must use the following equation of kinematics.
[tex]v_{f}=v_{o}+a*t[/tex]
But first we must convert the velocity from kilometers per hour to meters per second.
[tex]72[\frac{km}{h}]*[\frac{1000m}{1km}]*\frac{1h}{3600s} =20[m/s][/tex]
i)
Vf = final velocity = 20 [m/s]
Vo = initial velocity = 0 (stars from the rest)
a = acceleration [m/s²]
t = time = 4 [s]
[tex]20 = 0+a*4\\a=20/4\\a = 5[m/s^{2}][/tex]
ii)
Now we can calculate the distance with the following equation of the kinematics.
[tex]v_{f}^{2}=v_{o}^{2} +2*a*x[/tex]
where:
x = distance covered [m]
[tex]20^{2} =0 +2*5*x\\400=10*x\\x = 40 [m][/tex]
