A bike is a machine with two wheels that is used for both pleasure and transportation, and The cyclist is the only source of power by creating motion energy through pedaling. The bike can move forward in time with the front wheel because of the energy that moves a chain attached to the back wheel.A bike is a machine with two wheels that is used for both pleasure and transportation, and The cyclist is the only source of power by creating motion energy through pedaling. The bike can move forward in time with the front wheel because of the energy that moves a chain attached to the back wheel.