Write four uses of magnetic and frictional forceeach?
Answers
Frictional force
Walking
You could not walk without the friction between your shoes and the ground. As you try to step forward, you push your foot backward. Friction holds your shoe to the ground, allowing you to walk. Consider how difficult it is to walk on slippery ice, where there is little friction.
Writing
Writing with a pencil requires friction. You could not hold a pencil in your hand without friction. It would slip out when you tried to hold it to write. The graphite pencil led would not make a mark on the paper without friction.
A pencil eraser uses friction to rub off mistakes written in pencil lead. Rubbing the eraser on the lead wears out the eraser due to friction, while the particles worn off gather up the pencil lead from the paper.
Driving a car or riding a bicycle
Your car would not start moving if it wasn't for the friction of the tires against the street. With no friction, the tires would just spin.
Likewise, you could not stop without the friction of the brakes and the tires.
Magnetic force
Compass
A compass uses a magnet to direct its needle to the north pole. This is why magnets are said to have a north and south pole. The side that is attracted and points to the north is called the north pole, while the other end is the south pole. Children can easily learn about magnets in a compass by crafting one with a needle, cork and a bowl of water. Magnetize the needle by rubbing it with a strong magnet. Then, place the needle on top of a cork floating in water. It will point to the north.
Mag-Lev Trains
Magnetically levitated trains, known as mag-lev trains, use magnets under the cars to float above the magnetic tracks because the magnets are repelling each other. These types of trains use superconducting magnets and can travel up to 300 miles per hour. Mag-lev trains are used in countries such as Japan. The United States government is working on bringing the technology to America.
Compass
A compass uses a magnet to direct its needle to the north pole. This is why magnets are said to have a north and south pole. The side that is attracted and points to the north is called the north pole, while the other end is the south pole. Children can easily learn about magnets in a compass by crafting one with a needle, cork and a bowl of water. Magnetize the needle by rubbing it with a strong magnet. Then, place the needle on top of a cork floating in water. It will point to the north.
Mag-Lev Trains
Magnetically levitated trains, known as mag-lev trains, use magnets under the cars to float above the magnetic tracks because the magnets are repelling each other. These types of trains use superconducting magnets and can travel up to 300 miles per hour. Mag-lev trains are used in countries such as Japan. The United States government is working on bringing the technology to America.
Vending Machines
Coins are separated and sorted inside vending machines with magnets. These magnets sort out metal disks or slugs from the real coin money. Also, paper money and checks have magnetic dust in their ink. Vending machines and currency counters check the money for its magnetism to insure the money is genuine.
Holding Things
One of the most common uses of magnets is to hold things together. Paper shopping lists and your book report can be held up on refrigerator doors with fridge magnets. The magnets stick the paper to the door with its attraction to the metal in the door. Also, the actual refrigerator doors stay closed because of magnets in the door frames.
Electric Motors
Magnets are responsible for making electric motors and generators work. Moving a metal wire near a magnet produces electricity. Electric generators use steam, flowing water or another source of energy to spin wires through a magnetic field and create electricity. Every time you turn on a light or watch television, you can thanks magnets for helping produce electricity.
Explanation:
If we don't know the magnitude of the magnetic field directly then we can still use this method