E. Answer these questions. 1. What is a simple machine? List the various types of simple machines. 2 Name the three kinds of levers. Explain with diagrams how they are different from each other. 3. What is a pulley? How does it make our work easy? 4. What is a screw? Describe its use. 5. What is a wedge? How does it work as a simple machine?
Answers
1) Answer: simple machine any of several devices with few or no moving parts that are used to modify motion and the magnitude of a force in order to perform work.
Answer:
1. Simple machine are machines that makes our work easier and have few or no moving parts. Examples : wedge, screw, lever, pulley, inclined plane and the wheel and axle.
2. There are 3 types of levers . They are :
First class lever – the fulcrum is in the middle of the effort and the load.
Second class lever – the load is in the middle between the fulcrum and the effort.
Third class lever – the effort is in the middle between the fulcrum and the load.
3. A pulley is a wheel that carries a flexible rope, cord, cable, chain, or belt on its rim. A pulley makes our work easier because it helps to lift an object than lifting the heavy weight by hand.
4. Screw is simply an inclined plane around cylinders. Screws can be used to lift things or to hold them together.
5. Wedge is simply a triangular tool often made of metal , wood , stone or plastic. It is a simple machine that consists of two inclined planes, giving it a thin end and thick end. A wedge makes work easier by increasing the force applied to the object, although it applies the force over a shorter distance.