Answer in short. (any two )
1. Why do we need machines?
2. What are simple machines?
3. How does a Pulley make our work easier ?
4. How does the elbow joint work as a lever ?
Answers
Answer:
2.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. ... The simple machines are the inclined plane, lever, wedge, wheel and axle, pulley, and screw.
3.The pulley, a simple machine, helps to perform work by changing the direction of forces and making easier the moving of large objects. ... With this type of pulley — called a fixed pulley — pulling down on a rope makes an object rise off the ground. There are also movable pulleys and pulley systems.
Answer:
2) Simple machines that are widely used include the wheel and axle, pulley, inclined plane, screw, wedge and lever.
4) The elbow joint is an example of a third class lever, operating with the effort between the load and fulcrum. The distance between the elbow joint and the insertion site of the bicep tendon is very small, especially when it's compared to the distance between the elbow joint and the weight in your hand.