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Explanation:
2. A machine can be used to obtain a gain in speed. (ii) A machine can be used to lift a load in one direction by applying an effort in a convenient direction. (iii) A machine can be used to lift a heavy load by applying a less effort.
4. A jack is a mechanical lifting device used to apply great forces or lift heavy loads. A mechanical jack employs a screw thread for lifting heavy equipment. A hydraulic jack uses hydraulic power. The most common form is a car jack, floor jack or garage jack, which lifts vehicles so that maintenance can be performed.
5. Ideal machines are said to have parts which are weightless , frictionless and strings if any are inextensible. Practical machines have parts which have weights, friction and it causes some loss of work done. So these are the differences between Ideal Machine and Practical Machines.
6.The mechanical advantage of a machine is the ratio of the load (the resistance overcome by a machine) to the effort (the force applied). For an ideal (without friction) mechanism, it is also equal to: There is no unit for mechanical advantages since the unit for both input and output forces cancel out.
7. The ratio of the velocity of effort to the velocity of the load is called the velocity ratio of machine. It has no unit. Advertisement.