Answer:
a) dynamic equilibrium; b) No equilibrium; c) Static equilibrium; d) Dynamic equilibrium; e) Not equilibrium; f) Dynamic equilibrium.
Explanation:
a) In this case, the girder is in dynamic equilibrium, although there is movement it is realized at constant speed therefore there is no acceleration and the sum of forces is equal to zero.
b) There is no equilibrium since the velocity is decreasing it slows the girder, therefore the sum of forces will be equal to the product of mass by acceleration according to newton's second law.
c) In this case, the arms of the person are exercising each 100 lb, in order to keep the barbell stable, this allows the static equilibrium.
d) There is movement but however the jet will move at constant speed without any kind of acceleration, therefore it has a condition of dynamic equilibrium.
e) There is no balance as the rock falls and the acceleration due to gravity causes its speed to increase as it goes down.
f) In this case there is dynamic equilibrium as there was a deceleration movement however this force value given by the deceleration multiplied by the mass is not large enough to be able to move the box, due to the weight of the box plus the friction force between the box and the surface.
The amplitude of the pendulum is 5cm.
Amplitude is the maximum displacement of the wave from its mean position upwards or downwards.
As the graph of the motion of pendulum swings from +5cm to -5cm for each cycle, the magnitude of peak amplitude of the pendulum is 5 centimeters.
Learn about amplitude.
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waves in the ocean
waves in a wheat field
light
Which of the following does not represent a mechanical wave?
light
2) moon
3) Kuiper Belt object
4) meteor
2. Which explanation of the solar system best fits the observations of the planets and how they orbit the sun?
1) A comet hit the sun and sent off fragments that became the planets.
2) The gravity of a large, massive star passing the sun ripped off blobs of material from it that formed the planets.
3) The planets formed at the center of a collapsing spinning cloud of gas and dust.
4) The sun and planets formed from a collapsing spinning cloud of gas and dust.
Answer:
1: C. Kuiper Belt object
2: D. The sun and planets formed from a collapsing spinning cloud of gas and dust.
Explanation:
I just took the test!!!
Answer:
at the beginning:
when the plates are pulled apart:
Explanation:
The capacitance of a parallel-plate capacitor is given by
where
k is the relative permittivity of the medium (for air, k=1, so we can omit it)
is the permittivity of free space
A is the area of the plates of the capacitor
d is the separation between the plates
In this problem, we have:
is the area of the plates
is the separation between the plates at the beginning
Substituting into the formula, we find
Later, the plates are pulled apart to , so the capacitance becomes