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2 answers:
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The final kinetic energy of the ball is 2.45 J
Explanation:
We can solve this problem by using the law of conservation of energy.
In absence of frictional effect, the mechanical energy of the apple must be conserved during the fall. So we can write:
where :
is the initial potential energy, at the top
is the initial kinetic energy, at the top
is the final potential energy, at the bottom
is the final kinetic energy, at the bottom
By explicing the potential energy, we can rewrite the equation as:
where:
m = 0.5 kg is the mass of the apple
is the acceleration of gravity
is the initial height
is the final height
The initial kinetic energy is zero, since the ball starts from rest:
Therefore we can solve the equation for , the final kinetic energy of the ball:
Learn more about kinetic energy and potential energy:
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Faraday's law allows us to find the magnetic field that produces the emf in the rotating system is:
- The magnetic field is: B = 0.424 T
Faraday's law of induction states that when the magnetic flux changes in time, an induced electromotive force is produced.
fem =
where fem is the induced electromotive force and Ф the flux,
The magnetic flux is the scalar product of the field and the area.
In this case we have several turns, so the expression remains.
fem =
Indicate that the turns rotate at a constant frequency, therefore we can use the uniform rotational motion ratio.
θ = w t
We substitute
the maximum induced electromotive force occurs when the sine function is ±1
fem = N B A w
They indicate that the fem = 24 V, the number of the turn is N = 20, the area is A = 75 cm² = 75 10⁻⁴ m² and the frequency f = 60 Hz
Frequency and angular velocity are related.
w = 2π f
We substitute.
fem = N B A 2π f
Let's calculate.
B = 24 / 2pi 20 75 10-4 60
B = 0.424 T
In conclusion, using Faraday's law we can find the magnetic field that produces the emf in the rotating system is:
- The magnetic field is; B = 0.424 T
Learn more about Faraday's law here: brainly.com/question/24617581
Answer:
Explanation:
This is a problem based on time dilation , a theory given by Albert Einstein .
The formula of time dilation is as follows .
t₁ =
t is time measured on the earth and t₁ is time measured by man on ship .
A ) Given t = 20 years , t₁ = ? v = .4c
=1.09 x 20
t₁= 21.82 years
B ) Given t = 5 years , t₁ = ? v = .2c
=1.02 x 5
t₁= 5.1 years
C ) Given t = 10 years , t₁ = ? v = .8c
=1.67 x 10
t₁= 16.7 years
D ) Given t = 10 years , t₁ = ? v = .4c
=1.09 x 10
t₁= 10.9 years
E ) Given t = 20 years , t₁ = ? v = .8c
=1.67 x 20
t₁= 33.4 years