Answer:
The slower the train is moving, the less are the changes of the magnetic flux, thus the eddy currents become weaker.
Explanation:
A magnetic brakes is not a very efficient way of braking when a train is moving slowly because at low speeds, the changes in the magnetic flux are very less and so it causes the eddy current to become weaker.
Let us find the drag force which is proportional to the velocity of two conducting plates.
The EMF that is induced in the eddy currents are : 
The force which is due to the induced magnetic field is, 
Therefore, 
Here, force is directly proportional to the velocity of the two conducting plates.
Therefore, we can say that when the speed of the train is low, the magnetic flux changes are less and thus the eddy currents are weaker.
Answer:
12.7 m
Explanation:
The following data were obtained from the question:
Initial velocity (u) = 56.7 Km/hr
Maximum height (h) =..?
First, we shall convert 56.7 Km/hr to m/s. This can be obtained as follow:
Initial velocity (m/s) = 56.7 x 1000/3600
Initial velocity (m/s) = 15.75 m/s
Next, we shall determine the time taken to get to the maximum height. This can be obtained as follow:
Initial velocity (u) = 15.75 m/s
Final velocity (v) = 0 m/s
Acceleration due to gravity (g) = 9.8 m/s²
Time (t) =?
v = u – gt (since the ball is going against gravity)
0 = 15.75 – 9.8 × t
Rearrange
9.8 × t = 15.75
Divide both side by 9.8
t = 15.75/9.8
t = 1.61 secs.
Finally, we shall determine the maximum height as follow
h = ½gt²
Acceleration due to gravity (g) = 9.8 m/s²
Time (t) = 1.61 secs.
Height (h) =..?
h = ½gt²
h = ½ × 9.8 × 1.61²
h = 4.9 x 1.61²
h = 12.7 m
Therefore, the maximum height reached by the ball is 12.7 m
Answer:Dark minerals rich in iron and magnesium separate from light minerals rich in silica and aluminum.
Explanation: Metamorphic rocks are rocks formed as a result of the transformation of other existing rocks which can be Igneous or Sedimentary rocks,this transformation process is called METAMORPHISM. During metamorphism,rocks under Serious levels of stress which can lead to the separation of materials.
During this separation process,Dark minerals rich in iron and magnesium are separated from light minerals rich in silica and aluminum.
We want to find how many photons per second a laser emits given that we know the energy of a single photon and the power of the laser, we will get:
1.90712*10^18 photons per second.
So we know that the photon energy is 1.8 eV, and the laser power is:
P = 0.55 watts
Remember that:
1 watt = 1 J/s
And:
1 eV = 1.60218*10^(-19) J
Then we can convert the two values that we have so we have both in joules:
Power = P = 0.55 J/s
Energy = 1.8 eV = 1.8*(1.60218*10^(-19) J) = 2.883924*10^(-19) J
The number of photons emitted per second is just the quotient between the power and the energy of a single photon, we have:
Number = (0.55 J/s)/(2.883924*10^(-19) J) = 1.90712*10^18 photons per second.
If you want to learn more, you can read:
brainly.com/question/20343793
Answer:
0.33 m/s
Explanation:
The graph given is that of distance against time. The slope of such a graph gives the velocity of the object while travelling.
In this graph the change in distance for the last 6 seconds is given by;
The distance is : 10-8 = 2 m
The time in seconds is: 6 s
The velocity = 2/6 = 1/3 m/s
The velocity expressed in decimal form is : 0.33 m/s
