Question

A horse has to pull harder during the start of motion than later. Explain.

Answer 1

When a body is at rest, to bring it in motion, static friction needs to be overcome. However, while moving kinetic friction needs to be overcome. Now, limiting value of static friction is greater than kinetic friction. So, its harder to start motion than to sustain it. Hence, the horse has to apply less force when the cart is in motion.