"What is the energy density (energy per cubic meter) carried by the magnetic field vector in a small region of space in a EM wav
1 answer:
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Answer:
h = 3.3 m (Look at the explanation below, please)
Explanation:
This question has to do with kinetic and potential energy. At the beginning (time of launch), there is no potential energy- we assume it starts from the ground. There, is, however, kinetic energy
Kinetic energy = m
Plug in the numbers = (4.0)(
)
Solve = 2(64) = 128 J
Now, since we know that the mechanical energy of a system always remains constant in the absence of outside forces (there is no outside force here), we can deduce that the kinetic energy at the bottom is equal to the potential energy at the top. Look at the diagram I have attached.
Potential energy = mgh = (4.0)(9.8)(h) = 39.2(h)
Kinetic energy = Potential Energy
128 J = 39.2h
h = 3.26 m
h= 3.3 m (because of significant figures)
Answer:
<u>Searching in google I found the total mass and the radius of the ball (m = 1.5 kg and r = 10 cm) which are needed to solve the problem!</u>
The ball rotates 6.78 revolutions.
Explanation:
<u>Searching in google I found the total mass and the radius of the ball (m = 1.5 kg and r = 10 cm) which are needed to solve the problem!</u>
At the bottom the ball has the following angular speed:
Now, we need to find the distance traveled by the ball (L) by using θ=28° and h(height) = 2 m:
To find the revolutions we need the time, which can be found using the following equation:
(1)
So first, we need to find the acceleration:
(2)
By entering equation (2) into (1) we have:
Since it starts from rest (v₀ = 0):
Finally, we can find the revolutions:
Therefore, the ball rotates 6.78 revolutions.
I hope it helps you!