Any material that attracts iron or things made of iron is called a magnetmagnets propertiesAll magnets have two poles. Magnets exert forces on each other and are surrounded by a magnetic field.magnetic polesmagnetic poles are points on a magnet that have opposite magnetic qualities.The pole of a magnet that points to the north. Magnetic poles are always in pairs. You will never find a magnet that has only a north pole or only a south pole. magnetic forces result from spinning electric charges in the magnets. The force can either push the magnets apart or pull them together. The magnetic force is a universal force. It is always present when magnetic poles come near one another.The magnetic force between magnets depends on how the poles of the magnets line up. Like poles repel, and opposite poles attract A magnetic field exists in the region around a magnet in which magnetic forces can act. The shape of a magnetic field can be shown with lines drawn from the north pole of a magnet to the south pole. These lines map out the magnetic field and are called magnetic field lines. The closer together the field lines are, the stronger the magnetic field is. The lines around a magnet are closest together at the poles, where the magnetic force on an object is strongest. Whether a material is magnetic depends on the material's atoms.In most materials, such as copper and aluminum, the magnetic fields of the individual atoms cancel each other out. Therefore, these materials are not magnetic.But in materials such as iron, nickel, and cobalt, groups of atoms are in tiny areas called domains. The north and south poles of the atoms in a domain line up and make a strong magnetic field. Domains are like tiny magnets of different sizes within an object. The arrangement of domains in an object determines whether the object is magnetic. When domains move, the magnet is demagnetized, or loses its magnetic properties. 1. Dropping a magnet or hitting it too hard can move the domains. 2. Putting the magnet in a strong magnetic field that is opposite to its own can also move domains. 3. Increasing the temperature of a magnet can also demagnetize it. At higher temperatures, atoms in the magnet vibrate faster. As a result, the atoms in the domains may no longer line up. You can make a magnet from something made of iron, cobalt, or nickel. You can magnetize an iron nail if you rub it in one direction with one pole of a magnet. The domains in the nail line up with the magnetic field of the magnet. So, the domains in the nail become aligned. As more domains line up, the magnetic field of the nail grows stronger.how a magnet can pick up an unmagnetized object, such as a paper clip.When a magnet is close to a paper clip, some domains in the paper clip line up with the field of the magnet. So, the paper clip becomes a temporary magnet. The north pole of the paper clip points toward the south pole of the magnet. The paper clip is attracted to the magnet. When the magnet is removed, the domains of the paper clip become scrambled again. Each piece has its own north pole and south pole. A magnet has poles because its domains are lined up. Each domain within a magnet is like a tiny magnet with a north pole and a south pole. Even the smallest pieces of a magnet have two poles. Some magnets are made of iron, nickel, cobalt, or mixtures of those metals. Magnets made with these metals have strong magnetic properties and are called ferromagnets. Another kind of magnet is the electromagnet. This is a magnet made by an electric current. An electromagnet usually has an iron core. made from materials that are easy to magnetize. But they tend to lose their magnetization easily. Soft iron is iron that is not mixed with any other materials. It can be made into temporary magnets. Permanent magnets are difficult to magnetize. But they tend to keep their magnetic properties longer than temporary magnets do. Some permanent magnets are made with alnico—an alloy of aluminum, nickel, cobalt, and iron. A compass needle is a small magnet. And the tip that points to the north is the needle's north pole. Therefore, the point of a compass needle is attracted to the south pole of a magnet. A compass needle points north because the magnetic pole of Earth that is closest to the geographic North Pole is a magnetic south pole. A compass needle points to the north because its north pole is attracted to a very large magnetic south pole. Scientists think that Earth's magnetic field is made by the movement of electric charges in the Earth's core. The Earth's core is made mostly of iron and nickel. The inner core is solid because it is under great pressure. The outer core is liquid because the pressure is not as high. As Earth rotates, the liquid in the core flows. Electric charges move, which makes a magnetic field.aurora
We have , a 2.0 kg ball is resting at the top of a 20 m hill. if the ball rolls down the entire hill,We need to find how fast will it be going.Let's find out:
We know that,
Potential energy : This is the energy possessed by an object due to it's virtue of height and is given by , where m is mass , g is acceleration due to gravity & h is height !
Kinetic energy : This is the energy possessed by an object due to it's virtue of motion and is given by , where m is mass & v is the velocity of object !
~ A thermometer is an instrument that measures temperature. It can measure the temperature of a solid such as food, a liquid such as water, or a gas such as air. The three most common units of measurement for temperature are Celsius, Fahrenheit, and kelvin. The Celsius scale is part of the metric system.