1. Why is it easier to change the motion of a large toy car than a small toy car?

Because it is acted upon by balanced forces.

Toy cars use a variety of mechanisms to make them go, but they all store up potential energy. Although the elastic material inside is usually steel and not rubber, the principle is the same. By changing the shape of the material (usually a coil of metal) energy is stored and then released as motion.

Wind or electric energy force force of friction