mobil massa 800 kg bergerak lurus dengan kecepatan awal 72 km/jam setelah menempuh jarak 250 m kecepatan menjadi 108 km/jam. waktu tempuh mobil adalah...

With kinematic equation we can solve this question

First of all we can change the dimension of km/hour to m/s

72km/hour = 20m/s
108km/hour= 30m/s

And then we can plug this number into equation

v^2 = vo^2+2as
(30)^2= (20)^2 + 2a.250
900 = 400 + 500a
500a= 900-400
a= 500/500 = 1m/s^2

So we know the car is accelerated with 1 m/s /s from 20m/s to 30m/s

and to find how long does it take for 20m/s to 30m/s with a = 1m/s^2
We can use the equation
vf-vi = a.t
30-20 = 1 .t
t= 10s