A ball is released from the top of a hill. How fast is the ball going when it reaches the base of the hill? Approximate g as 10
2 answers:
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<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>
Answer:
(we need the mass of the astronaut A)
Explanation:
We can solve this by using the conservation law of the linear momentum P. First we need to represent every mass as a particle. Also we can simplify this system of particles by considering only the astronaut A with an initial speed of 0 m/s and a mass
and the IMAX camera with an initial speed
of 7.5 m/s and a mass
of 15.0 kg.
The law of conservation says that the linear momentum P (the sum of the products between all masses and its speeds) is constant in time. The equation for this is:
By the law of conservation we know that
For (final linear momentum) we need to treat the collision as a plastic one (the two particles stick together after the encounter).
So:
The current is defined as the amount of charge transferred through a certain point in a certain time interval:
where
I is the current
Q is the charge
is the time interval
For the lightning bolt in our problem, Q=6.0 C and
, so the average current during the event is
where
I is the current
Q is the charge
For the lightning bolt in our problem, Q=6.0 C and