Question

What is the acceleration of the car when vx = 16.9 m/s ?

Answer 1

Since the car had to begin initially at a certain point, therefore the initial velocity is equal to zero, Vi = 0. Vx will be the the fial velocity equal to 16.9 m/s. Time "t" is conditional. The equation for acceleration is a = Vf - Vi/t.

Formula: a = Vf - Vi/t

a = 16.9 m/s - 0/t

a = 16.9 m/s/t

Answer 2

There is no Vx(t). So let us assume it is = (0.910 m/s^3)t^2.
Since a = dv/dt,

a(t) = 0.91*2t = 1.82t
To look for the t at which v = 16.9 m/s
16.9 = 0.91*t^2

t = sqrt(16.9/0.91) = 4.31 s
a(4.31) = 1.82*4.31

=~7.84 [m/s^2] would be the answer.