Propulsion is the process that moves an object forward, using various forces. In vehicles like cars and airplanes, engines convert fuel into energy, creating thrust that pushes them ahead. For example, a jet engine uses combustion to generate high-speed exhaust gases, propelling the aircraft into the sky. In the case of boats, propulsion can come from propellers or sails. A propeller spins in the water, creating a difference in pressure that moves the boat forward. Meanwhile, sails catch the wind, harnessing its energy to glide across the water. Both methods demonstrate how different forces can achieve movement.