You want to create a device to warm food that is safe. Which type of electromagnetic wave would be most useful to investigate?
1 answer:
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Answer:
The angle of banked curve that makes the reliance on friction unnecessary is
Explanation:
In order the car to stay on the curve without friction, the net force in the direction of radius should be equal or smaller than the centripetal force. Otherwise the car could slide off the curve.
The only force in the direction of radius is the sine component of the weight of the car
The cosine component is equivalent to the normal force, which we will not be using since friction is unnecessary.
Newton’s Second Law states that
Also, the car is making a circular motion:
Combining the equations:
Finally the angle is
<span> (a) does an electric field exert a force on a stationary charged object?
Yes. The force exerted by an electric field of intensity E on an object with charge q is
</span>
<span>As we can see, it doesn't depend on the speed of the object, so this force acts also when the object is stationary.
</span><span>(b) does a magnetic field do so?
No. In fact, the magnetic force exerted by a magnetic field of intensity B on an object with charge q and speed v is
</span>
where
is the angle between the direction of v and B.
As we can see, the value of the force F depends on the value of the speed v: if the object is stationary, then v=0, and so the force is zero as well.
<span>(c) does an electric field exert a force on a moving charged object?
Yes, The intensity of the electric force is still
</span>
<span>as stated in point (a), and since it does not depend on the speed of the charge, the electric force is still present.
</span><span>(d) does a magnetic field do so?
</span>Yes. As we said in point b, the magnetic force is
And now the object is moving with a certain speed v, so the magnetic force F this time is different from zero.
<span>(e) does an electric field exert a force on a straight current-carrying wire?
Yes. A current in a wire consists of many charges traveling through the wire, and since the electric field always exerts a force on a charge, then the electric field exerts a force on the charges traveling through the wire.
</span><span>(f) does a magnetic field do so?
Yes. The current in the wire consists of charges that are moving with a certain speed v, and we said that a magnetic field always exerts a force on a moving charge, so the magnetic field is exerting a magnetic force on the charges that are traveling through the wire.
</span><span>(g) does an electric field exert a force on a beam of moving electrons?
Yes. Electrons have an electric charge, and we said that the force exerted by an electric field is
</span>
<span>So, an electric field always exerts a force on an electric charge, therefore on an electron beam as well.
</span><span>(h) does a magnetic field do so?
Yes, because the electrons in the beam are moving with a certain speed v, so the magnetic force
</span>
<span>is different from zero because v is different from zero.</span>
Yes. The force exerted by an electric field of intensity E on an object with charge q is
</span>
<span>As we can see, it doesn't depend on the speed of the object, so this force acts also when the object is stationary.
</span><span>(b) does a magnetic field do so?
No. In fact, the magnetic force exerted by a magnetic field of intensity B on an object with charge q and speed v is
</span>
where
As we can see, the value of the force F depends on the value of the speed v: if the object is stationary, then v=0, and so the force is zero as well.
<span>(c) does an electric field exert a force on a moving charged object?
Yes, The intensity of the electric force is still
</span>
<span>as stated in point (a), and since it does not depend on the speed of the charge, the electric force is still present.
</span><span>(d) does a magnetic field do so?
</span>Yes. As we said in point b, the magnetic force is
And now the object is moving with a certain speed v, so the magnetic force F this time is different from zero.
<span>(e) does an electric field exert a force on a straight current-carrying wire?
Yes. A current in a wire consists of many charges traveling through the wire, and since the electric field always exerts a force on a charge, then the electric field exerts a force on the charges traveling through the wire.
</span><span>(f) does a magnetic field do so?
Yes. The current in the wire consists of charges that are moving with a certain speed v, and we said that a magnetic field always exerts a force on a moving charge, so the magnetic field is exerting a magnetic force on the charges that are traveling through the wire.
</span><span>(g) does an electric field exert a force on a beam of moving electrons?
Yes. Electrons have an electric charge, and we said that the force exerted by an electric field is
</span>
<span>So, an electric field always exerts a force on an electric charge, therefore on an electron beam as well.
</span><span>(h) does a magnetic field do so?
Yes, because the electrons in the beam are moving with a certain speed v, so the magnetic force
</span>
<span>is different from zero because v is different from zero.</span>