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AlexFokin [52]
4 years ago
8

A mini rail gun made of a copper rod of mass m and radius r rests on two parallel copper rails that are a distance L apart and o

f length d. A magnetic field of magnitude B is directed perpendicular to the rod and the rails. When current is applied to the parallel copper rails, the rod rolls along the rails without slipping. If the rod starts from rest, what is the speed of the rod as it leaves the rails?
Physics
1 answer:
ira [324]4 years ago
7 0

Answer:

Explanation:

Magnetic Force on the rod  F = Bi L

Work done by this force = F X d

=  Bi Ld

This energy is converted into both rotational and linear kinetic energy

= 1/2 I ω² + 1/2 mv²

= 1/2 x 1/2 m r²ω²+ 1/2 mv²

= 1/4 m v² + 1/2 mv²

= 3/4 mv²

So according to conservation of energy

Bi Ld =  3/4 mv²

v = \sqrt{\frac{4BiLd}{3m} }

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Svetllana [295]

Answer:

Explanation:

Moving a magnet might cause a change in the magnetic field going through the solenoid. Whether or not it will change depends on the movement.

According to Faraday's law of induction a voltage is induced in a coil by a change in the magnetic flux. Magnetic flux is defined as the dot product of the magnetic field (a vector field) by the area enclosed by a loop of the coil.

\Phi B = -\int{B} \, dA

The voltage is induced by the variation of the magnetic flux:

\epsilon = -N * \frac{d \Phi B}{dt}

Where

ε: electromotive fore

N: number of turns in the coil

ΦB: magnetic flux

Moving the magnet faster would increase the rare of change of the magnetic flux, resulting in higher induced voltage.

Turning the magnet upside down would invert the direction of the magnetic field, reversing the voltage induced.

5 0
3 years ago
Calculate the potential difference across a 25- resistor if a 0.3-A current is flowing through it.
alekssr [168]

Voltage = (current) x (resistance)

Voltage = (0.3 A) x (25 ohms)

Voltage = (0.3 x 25) (A-Ω)

<em>Voltage = 7.5 volts</em>

8 0
3 years ago
Read 2 more answers
Which type of mine involves digging tunnels and shafts deep underground?
mel-nik [20]

The mine involves digging tunnels and shafts deep underground is the underground mining.

<h3>What is mining?</h3>

Mining is the digging of the Earth deep down in search of some precious elements or resources found on Earth.

Underground mining is the digging down into the earth in order to create tunnels. The shafts need to be inserted into those tunnels so that it reaches the deposits of resources.

Thus, underground mining involves digging tunnels and shafts deep underground.

Learn more about mining.

brainly.com/question/14277327

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7 0
2 years ago
A car is going south on I-69 at 33 m/s (74 mph). The car has good brakes so its maximum braking acceleration is – 8.5 m/s^2 . Tr
dmitriy555 [2]

Answer:

1.69515 seconds

Explanation:

t = Time taken

u = Initial velocity

v = Final velocity

s = Displacement

a = Acceleration

v^2-u^2=2as\\\Rightarrow s=\frac{v^2-u^2}{2a}\\\Rightarrow s=\frac{0^2-33^2}{2\times -8.5}\\\Rightarrow s=64.06\ m

The distance between the traffic and the car after braking is 120-64.06 = 55.94 m

Time = Distance / Speed

\text{Time}=\frac{55.94}{33}\\\Rightarrow \text{Time}=1.69515\ seconds

The reaction time cannot be more than 1.69515 seconds

4 0
3 years ago
A car speeds over a hill past point A, as shown in the figure. What is the maximum speed the car can have at point A such that i
Lubov Fominskaja [6]

Answer:

11.8 m/s

Explanation:

At the top of the hill, there are two forces on the car: weight force pulling down (towards the center of the circle), and normal force pushing up (away from the center of the circle).

Sum of forces in the centripetal direction:

∑F = ma

mg − N = m v²/r

At the maximum speed, the normal force is 0.

mg = m v²/r

g = v²/r

v = √(gr)

v = √(9.8 m/s² × 14.2 m)

v = 11.8 m/s

3 0
3 years ago
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