B. Short/Long Answer Questions
1. When is work said to be done by a force ?
2. What is energy?
3. What do you understand by a machine ?
4. What is the principle on which a machine works?
5. State two functions of a machine.
Answers
Answer:
1 when a force acts upon an object to cause a displacement of the object , it is said that work is done by a force
2 the capacity of doing work
3 a machine is a mechanical device that uses power to apply forces and control movement to perform an intended action . they also include computers and sensors that monitor performance and plan movement often called as mechanical systems
4 Principle of a Machine: The work output of a machine is equal to the work input. All machines work on the principle that when the effort is smaller than the load, it has to move a greater distance in order to achieve the same work.
5 A machine has two functions: transmitting definite relative motion and transmitting force. These functions require strength and rigidity to transmit the forces.