128 QUESTIONS ON THE 



MECHANICAL POWERS. 



370. How many mechanical powers are there, and 

 name them? 



371 . What was the cause that originated the invention 

 of mechanical powers ? 



372. Which was the first mechanical power invented ? 

 . 3/3. How many kinds of Levers are there ? 



374. What is meant by the fulcrum in leverage ? 



375. Explain the different kinds of levers, and their 

 action ? 



376. What is the proportional gain in levers of the 

 first and second kinds? 



377. In which kind of lever is It that there is a loss of 

 power, and why is it used ? 



378. If there be a gain in power, what loss is it that 

 there is then necessarily incurred r 



379. To what kind of lever are the following articles 

 referred ; the hammer in drawing a nail, a pair of scis- 

 sors, the rudder of a vessel, pincers, a steel-yard, a door, 

 and the oars of a boat ? 



380. Describe the Wheel and Axle, and to what other 

 power may this be referred ? 



381. Required the advantages gained in the wheel and 

 axle. 



382. To what uses are the wheel and axle applied? 



383. Describe the Pulley. 



384. What advantage is gained in a single fixed pulley ? 



385. Required the advantage gained in a single move- 

 able pulley. 



386. Required the advantage gained in a series of 

 moveable pulleys. 



387. To which of the mechanical powers is the adze 

 referred ? 



388. Which mechanical power is that which offers the 

 greatest advantages, and why ? 



38Q. Describe the Inclined Plane. 



390. If two inclined planes are placed flat together, 

 what other mechanical power will it make ? 



391. What advantage is obtained from the inclined 

 plane ? 



