Answer:
Yes we can find the initial velocity of car without finding acceleration.
u = 10 m/s.
Explanation:
Given that
s=20 m
Car takes 4 s to come in rest.
We know that when acceleration is constant then we can apply motion equation
[tex]v=u+at[/tex] ----------1
[tex] s=ut+\dfrac{1}{2}at^2[/tex] ------2
From equation 1 and 2
[tex]s=ut+\dfrac{1}{2}t^2\left (\dfrac{v-u}{t} \right )[/tex]
So we can say that
[tex]s= \left(\dfrac{v+u}{2}\right)t[/tex]
Given that the velocity of car at final condition will be zero (v=0)
[tex]s= \left(\dfrac{0+u}{2}\right)t[/tex]
[tex]s= \left(\dfrac{u}{2}\right)t[/tex]
From the above equation we can find the initial velocity of car without finding the acceleration
[tex]20= \dfrac{u}{2}\times 4[/tex]
u = 10 m/s
