Here we have to calculate the distance covered by a car.
as per the question the car was initially at rest.
hence the initial velocity of the car [u] is zero.
the final velocity of the car is given as 21 m/s
the acceleration of the car is 3.5 m/s^2
from kinematics we know that the equation of motion is-
[tex]S=\frac{v^2-u^2}{2a}[/tex]
here S is the distance traveled by the car and v is the final velocity
Hence [tex]S=\frac{[21]^2-0^2}{2*3.5} metre[/tex]
[tex]S=\frac{441}{7} metre[/tex]
S=63 metre
hence the distance traveled by the car is 63 metre when it gained the velocity of 21 m/s
