If the force is 3,000 N and the acceleration is 2 m/s/s. The mass of the car is 1,500 grams (or whatever unit of mass or weight is used in the answer- pounds, kilograms e.t.c.).
The formula to find the kinetic energy is:
Ek= 1/2 × m × v^2
1. Ek= 1/2×15×3^2
= 67.5 J
2.Ek= 1/2×8×4^2
=64 J
3.Ek= 1/2×12×5^2
= 150 J
4.Ek= 1/2×10×6^2
= 180 J
So the fourth dog has the most kinetic energy.