Answer
$v = 110~km/h$
Work Step by Step
We know that;
$KE = \frac{1}{2}mv^2$
We can equate the kinetic energy of the car and the kinetic energy of the truck to find the required speed of the car:
$KE_{car} = KE_{truck}$
$\frac{1}{2}(1000~kg)v^2= \frac{1}{2}(20,000~kg)(25~km/h)^2$
$v^2 = (20)(25~km/h)^2$
$v = \sqrt{(20)(25~km/h)^2}$
$v = 110~km/h$
