Introduction to Machines Answers

A machine can never be 100% efficient because some work is always lost due to which factor?

Which refers to the ratio of output work to input work of a machine expressed as a percent?

Which statement best describes why a machine is useful?

What is impossible for a machine to do?

Tas watches as his uncle changes a flat tire on a car. His uncle raises the car using a machine called a jack. Each time his uncle pushes down on the jack handle, the car rises up. Tas sketches the jack and labels it using the symbols F, to represent force, and d, to represent distance. He uses large and small letters to compare the sizes of the forces and distances.Which set of labels is correct for the side of the jack that Tas’s uncle pushes on?

While researching machines and how they work, Tika finds several online sites that discuss how force and distance are related to work done by a machine.How should Tika most likely describe this relationship between force and distance to her study group?

A machine has an efficiency of 70%. How much work does the machine do when 20,000 J of work is done on it?

Mr. Franklin uses a machine that has an efficiency of 80%. The machine applies a force of 800 N through a distance of 20 m. Mr. Franklin applies a force of 50 N on the machine.Through what distance does Mr. Franklin apply the force?

What is the mechanical advantage of a machine that applies a force of 1000 N to an object when a force of 500 N is applied to the machine?

Percy pulls on a rope that is held up by a pulley, like the one shown. The pulley is near the ceiling, and the other end of the rope is attached to a crate. Percy applies 75 N of force to the rope, and the rope lifts the crate by applying a force of 75 N.