Magnetic forces/magnetic fields

In summary, a magnetic field is an invisible force surrounding a magnet or electric current that causes attraction or repulsion with other magnetic objects. This is due to the alignment of magnetic domains and is affected by distance, strength, and material properties. Magnetic forces have many practical applications, including electric motors, MRI machines, and compass navigation. While everyday magnetic fields are generally not harmful to humans, strong and prolonged exposure can have temporary or long-term health effects.
  • #1
stryker123
11
0

Homework Statement



A .2Kg metal rod carrying a current of 10A glides on two horizontal rails .5m apart. What vertical magnetic field is required to keep the rod moving at a constant speed if the coefficient of kinetic friction is .1?


Homework Equations





The Attempt at a Solution



F (magnetic) = B I L (B is vertical to L)
F (friction) = mew * mg
where mew = 0.1 =coeffi of friction
------------------------------...
BIL = 0.1 * 0.2*9.8
B = 0.1 * 0.2*9.8/10*0.5
B = 0.0392 Tesla vertically

acceleration of rod = m dv/dt = F (mag) - F (fric) = 0
dv/dt =0
v = constant


is this the right setup? or am I heading no where?
 
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  • #2


Your setup and solution are correct. To keep the rod moving at a constant speed, the magnetic force must equal the frictional force. Using the equations you provided, you correctly solved for the required vertical magnetic field. Good job!
 

1. What is a magnetic field?

A magnetic field is an invisible force that surrounds a magnet or electric current, causing other magnetic objects to either attract or repel. It is represented by lines of force that indicate the direction and strength of the field.

2. How do magnetic forces work?

Magnetic forces work by the interaction of magnetic fields between two objects. Opposite poles (north and south) of magnets attract each other, while like poles repel. This is due to the alignment of magnetic domains within the objects.

3. What factors affect the strength of a magnetic field?

The strength of a magnetic field is affected by the distance between the objects, the strength of the magnet or current, and the magnetic properties of the materials involved. The force also decreases as the distance between objects increases.

4. What are some real-life applications of magnetic forces?

Magnetic forces have many practical applications, such as in electric motors and generators, MRI machines, maglev trains, and compass navigation. They are also used in speakers and headphones to convert electrical signals into sound waves.

5. Can magnetic fields be harmful to humans?

In general, magnetic fields from everyday objects are not harmful to humans. However, extremely strong magnetic fields, such as those found in MRI machines, can have temporary effects on the body, such as causing dizziness or nausea. Long-term exposure to high levels of magnetic fields can also have health effects, such as an increased risk of cancer.

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