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Middle school physics - NGSS
Course: Middle school physics - NGSS > Unit 2
Lesson 3: Magnetic forcesMagnetic forces
NGSS.MS:
MS‑PS2‑3
, MS‑PS2.B.1
, MS‑PS2.B
Magnetic forces can be found all around us. Did you know they can be attractive or repulsive? This all depends on the position of the magnets and if the same or opposite magnetic poles are facing each other. The strength of a magnetic force depends on the strength of the magnets and the distance between them.
Created by Khan Academy.
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Is there a force which increases when the distance increases?(13 votes)
Elastic forces tend to do this. Imagine stretching a rubber band. The more you stretch it, the more force is exerted.(23 votes)
so what exactly is the difference between an electrical force and a magnetic force?? apart from the units that are used(6 votes)
Hi,
A magnetic force is when magnetic forces(North and South Poles) interact with each other. This may be shown by movement(for an example: Your refrigerator magnet attracts, moves toward the fridge, and stick onto the fridge) between these magnetic poles.
An electrical force is when electrons(very, VERY, VERY small particles that produce electrical charges) move and interact with each other(for an example: When you touch a doorknob, you feel a shock because electrons are traveling between you and your hand).
Hope this helps!(9 votes)
- what if a make a metal car and put a big horse shoe magnet infront of it would the car move forward(4 votes)
Even with a very strong and large magnet, it would still not be able to directly propel a metal car forward on its own. The magnetic force generated by a magnet, no matter how strong, is generally not powerful enough to overcome the inertia and resistance of a car's mass and friction with the ground.
To move a car forward, you need a propulsion system that can generate a significant amount of force to overcome these factors. In most cases, cars are propelled by internal combustion engines, electric motors, or other types of propulsion systems that convert fuel or energy into mechanical motion.
While a strong magnet can have a significant magnetic field and exert a strong force on magnetic materials, its influence diminishes rapidly with distance. The magnetic force also primarily affects materials that are attracted to magnets, such as iron or steel, and not necessarily the entire car.
In summary, even a very strong and big magnet would not be able to move a metal car forward on its own. Other forms of propulsion systems are needed to generate the necessary force and power to move a car.(4 votes)
- why is magentic energy important(3 votes)
They're important for a lot of things, such as the train example shown in the video, or cranes used to lift large pieces of metal.(4 votes)
Others (magnets) are so strong that even tiny ones can be almost impossible to pull apart. could you explain this statement more ?(3 votes)
It's saying that some magnets are so strong that even when the magnet it's self is small, the force is strong.(4 votes)
- If all magnets have north and south poles, how do those magnetic balls work in satisfying videos of people putting stuff together? Are their north and south poles all over them?(3 votes)
- All magnets have north and south poles at a designated area. For magnetic balls, their poles are on their caps.(3 votes)
- A magnetic force is when magnetic forces(North and South Poles) interact with each other. This may be shown by movement(for an example: Your refrigerator magnet attracts, moves toward the fridge, and stick onto the fridge) between these magnetic poles.
An electrical force is when electrons(very, VERY, VERY small particles that produce electrical charges) move and interact with each other(for an example: When you touch a doorknob, you feel a shock because electrons are traveling between you and your hand).
Hope this helps!(4 votes) 
But, why does north repel north and south attract north?(3 votes)- This happens because magnets create something called a "magnetic field" around them. The magnetic field is like an invisible force that extends around the magnet. When two magnets come close, their magnetic fields interact. When the magnetic fields interact, they can either push or pull on each other, depending on their poles.(2 votes)
- what can you do with to magent and the other magent.(3 votes)
- With two magnets, you can do several interesting things! Here are a few fun experiments and activities you can try:
Attraction and Repulsion: Explore how magnets attract and repel each other. Hold one magnet in your hand and bring it close to another magnet. Observe how they either stick together (attract) or push each other away (repel) depending on their poles.
Magnetic Fields: Place a piece of paper over a magnet and sprinkle iron filings on top. Gently tap the paper, and you'll see the iron filings align themselves along the magnetic field lines, revealing the shape of the magnetic field. This helps visualize the invisible force surrounding the magnet.
Magnetic Levitation: Using two magnets with the same pole facing each other (like two north poles), you can try to make one magnet float in the air. Hold one magnet in your hand, and bring it close to the other magnet placed on a surface. You may find that the magnet on the surface can levitate or hover above the other magnet due to the repulsion force.
Magnetic Pick-Up: Attach a small magnet to a string or a popsicle stick and use it as a magnetic pick-up tool. You can use it to attract and retrieve small metal objects like paperclips or screws that are hard to reach.
Magnetic Compass: Rub one end of a magnet against a needle several times in the same direction. Then, carefully place the needle on a small piece of cork or a bowl filled with water. The needle will align itself with the Earth's magnetic field, acting as a simple compass.(2 votes)
- If you take two south poles and take them away from eachother does the force increase?(2 votes)
Hi,
no it would not increase it would decrease the further away they are the more they decrease. 2 south poles put together would repel elastic force would increase the further each side gets away from eachother. Rubber bands have elastic force.
Hope this helps.(3 votes)
Video transcript
- [Instructor] Let's talk about magnets and magnetic forces. Magnets are these neat
objects that are able to attract metals like iron. Magnets are used in all sorts of things, from holding paper on your refrigerator, to computers, to compasses. So magnets can be used
to stick things together, point us in the right
direction, and even lift things, and they do this through magnetic forces. If you've handled two magnets,
you felt magnetic forces, even when the magnets
weren't touching each other. That's because magnetic
forces are non-contact forces, which just means they
can affect other objects they aren't even touching. Magnets will attract or repel each other, and this attraction or
repulsion is a magnetic force. But magnetic forces don't
affect everything the same way. Otherwise, a magnet would stick to you, not just a refrigerator. In this video, we're going to
talk about the magnetic forces between two magnets. So why do magnet sometimes
attract each other and other times repel each other? Well, this has to do with the
orientation of the magnets. Orientation is really just a fancy word for how the magnets are positioned
compared to one another. You see, it turns out that
each magnet has a north and south pole, but what does this have to do
with attraction or repulsion? Well, as you may have
heard, opposites attract. So, if you face the
north pole of one magnet to the south pole of
another magnet, guess what? They will be attracted to each other. But if you turn one of
those magnets around so that you have two north
poles facing each other, they will repel. And the same thing would happen if it was two south
pulse facing each other. So the direction of the magnetic
force completely depends on the orientation of the magnets. Orientation, though, is just one thing that affects magnetic forces. The strength of magnetic forces depends on a couple of things. For one, distance. If you've ever held two magnets, you may have noticed that
when you move them closer, they seem to almost jump together. Or if you try to push
two light poles together, they get harder and
harder to hold together the closer you get. This is because magnetic
forces depend on distance. The closer the two magnets are together, the stronger the force between them. So, as the distance decreases,
the force increases, but the farther away they are, the weaker the magnetic force is. So, distance increases; force decreases. The other big factor that affects how strong a magnetic force is... Well, the magnets themselves. Sub magnets are really weak, like a lot of refrigerator magnets. Others are so strong that even tiny ones can be almost impossible to pull apart. Some of these stronger
magnets are even used to make high-speed trains
levitate off the ground. And yes, this rectangle
is supposed to be a train. While my drawing isn't amazing, the fact that magnetic forces
can levitate a train is.