Machines are useful for all kinds of things. Machines can give you a break from using your hands.
Some yes,some,no. There are uesful and not-so-useful in both sexes. It really depends on your definition of "useful".
Its Useful For Us We Use It For Cooking And To Keep Us Warm In The Cold Days Also We Use It For Turning On Our Machines.
Models are useful in science, because it is easier for some to understand then words.
yes some chemical reactions are harmful to us. as digestion of food, photosynthesis, decomposition of organic waste are some examples of the useful chemical reactions.
With out batteries some electronic machines , objects etc. do not work . Most of the machines , objects etc. consist and needs batteries (NOTE :- ( I HOPE MY ANSWER IS CORRECT ))
Electromagnets are useful because some machines need magnets that can stop being magnetic. In junkyards, some machines need to pick up metallic objects, so they need magnets that can turn on and off, which is where a electromagnet becomes useful.
World
for doing works
A machine saves you force, changes distance, and changes direction. Those are the three ways in science that why machines are useful.
Simple machines are not bad.
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Some of the cheaper sewing machines on the market consist of various Brother and Singer machines. Brother and Singer sewing machines can go for as cheap as $200 on Amazon. Though these machines are cheap, it doesn't mean that they are bad. Cheaper machines are useful for a person who just enjoys sewing as a hobby. If you are a professional, then it is a good idea to purchase a more expensive sewing machine.
in making machines
Hydraulic machines are useful in construction as they are force magnifiers. This means that a small input force can be made into a large input force. ^_^
Machines are useful to me because of all kinds of things. Machines can give you a break from using your hands.It also manages power to accomplish a task.also machines do stuff like cleaning your house so you can take a rest.It also makes time past for so people.
Friction converts mechanical energy into heat, which is rarely useful, and which can never be recovered in its entirety. Due to conservation of energy, this heat energy is not available for other things, i.e., for useful work.
Some useful applications of electrostatic charges include inkjet printing, electrostatic precipitators for air pollution control, and powder coating in manufacturing processes. The principles of electrostatic charges are also utilized in photocopying machines and laser printers.