Q. Ideal machine is one whose efficiency is 100% (yes/no)?

yes.

Q. The efficiency of a lifting machine is the ratio of

• output to the input
• work done by the machine to the work done on the machine
• mechanical advantage to the velocity ratio

Q. A machine having an efficiency less than 50%, is known as self locking machine.

Q. Lifting Machine :- It is a device, which enables us to lift a heavy load W, by a comparatively small effort (P).

Q. Ideal Machine :- If the efficiency of the machine is 100%, i.e. if output is equal to input, then the machine is said to be a perfect or ideal machine.

Q. Reversible machine :-  If a machine is capable of doing some work in the reverse direction, after the effort removed, then the machine is known as reversible machine. The condition for a machine to be reversible is that its efficiency should be more than 50%.

Engineering Mechanics or Applied Mechanics Important Question

Find out Newton’s Law of Motion. 

Q. what are the Newton’s Law of motion?

There are three laws of motion given by the Newton:

1. First Law of motion: – First law of motion states that a body continuous it state of rest or in uniform motion until external force acts on the body.
2. Second Law of motion: – Second law of motion states that the rate of change of momentum is directly proportional to impressed force, which act in same direction of the force.
3. Third Law of motion: – Third law of motion states that every action there is an equal an opposite reaction.

Q. Define mass?

The matter contained in the body is called mass. Unit of mass is Kg. Mass of the body remain constant irrespective of its position.

Q. Define Weight?

The force, by which the body attracted towards the center of earth, is called weight. Unit of weight (N). Weight of the body does not remain constant.