A small horse has the same amount of kinetic energy as a larger horse moving at the same speed is a FALSE concept.
Step-by-step explanation:
When an object is in motion, it has energy named kinetic energy. Kinetic Energy is the work that is needed to make a given mass non-stationary. The kinetic energy depends on the mass of the object.
As we increase the mass of an object, the kinetic energy will increase in the same proportion. Due to the difference between the mass of both horses, there will be a difference between their kinetic energy irrespective of their speed.