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:
(a) 80.36 m/s^2
(b) 0.0933 second
Explanation:
initial velocity, u = 7.5 m/s
final velocity, v = 0 m/s
distance moved, s = 0.350 m
(a) Let a be the deceleration.
Use third equation of motion
a = 80.36 m/s^2
Thus, the deceleration is 80.36 m/s^2.
(b) Let the time taken is t
Use first equation of motion
v = u + a t
0 = 7.5 + 80.36 x t
t = 0.0933 second
Answer:
-0.55m/s
Explanation:
Given that: For the boy
Weight = 745N
Velocity = +0.35 m/s
Mass of the boy = ?
g = 9.81m/s^2
W = mg
745 = m×9.81
m = 75.94kg
For the girl
Given that:
Weight = 477 N
g = 9.81m/s^2
m = ?
W = mg
477 = m×9.81m/s^2
m = 48.62kg
To solve for the v of the girl, the two has to add up
48.62kg×v + 75.94kg×+0.35 m/s = 0
48.62v + 26.579 = 0
48.62v = - 26.579
v = -26.579/48.62
v = -0.5466
v = -0.55m/s
Hence, the velocity of the girl is -0.55m/s.
The negative sign is as a result of the two of them moving is opposite direction.
When visible light<span> in air enters a </span>medium<span> such as glass, the velocity of </span>light<span> decreases ... 3 by representing incident </span>light<span> as parallel </span>waves<span> with a </span>uniform<span> wavelength . ... Thus, they bunch up and stay bunched up as they run </span>through<span> the water. ... </span>wave<span> and the water </span>would<span> be the </span>medium<span> into which the </span>light wave<span> is </span>traveling<span>.</span>
Answer:
the element that takes part in a chemical reactions
there are usually two or more reactants in chemical reactions
except decomposition reactions
