Human beings use machines to save time and increase productivity when doing work. Machines are used to lift and move heavy objects and to reduce the amount of effort and energy people use in working. Machines also eliminate some of the risks involved in workplaces.
People use two types of machines: simple machines and compound machines. Types of simple machines include ramps, wedges, pulleys, gears, levers, inclined planes and hydraulic systems. Compound machines are machines that have two or more simple machines to function effectively. Examples include bicycles, cranes and bulldozers. Machines are used in simple tasks such as hitting a nail and in heavy tasks such as moving heavy metal and soil.