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A frictionless pendulum with a mass of 0.4 kg and a length of 2.1 m starts at point A, at an angle 0 of 60°. As it swings downward, it passes through point B, which is 30 degrees from equilibrium. What is the kinetic energy of the pendulum at point B?
A) 3.9 J
B) 3.0 J
C) 1.1 J
D) 4.1 J
Answers
The conservation of mechanical energy allows finding the result for the speed of the pendulum when it is at 30º is:
The speed is: 3.88 m / s
The conservation of mechanical energy is a theorem of greater importance in physics and ordinary life, it states that if there is no friction force the total mechanistic energy remains constant at all points.
Mechanical energy is the sum of kinetic energy plus all potential energies. In the attachment we see a diagram of the pendulum's movement at the two points of interest.
They indicate that the pendulum is released from an initial angle of θ₁ = 60º, let's find the mechanical energy at that point.
Em₀ = U = m g h
Where the height is measured from the lowest point of the movement.
h = L - L cos tea1 = L (1 cos tea1)
The second point of interest occurs for θ₂ = 30º.
At this point part of the energy is indica and part gravitational potential.
[tex]Em_f[/tex] = K + U₂
[tex]Em_f[/tex] = ½ m v² + m g h ’
There is no friction in the system, therefore mechanical energy is conserved.
Em₀ = Em₀_f
mg L (1 - cos θ₁) = ½ m v² + m g L (1 - cos θ₂)
v² = 2g L (cos θ₂ - cos θ₁)
Let's calculate.
v² = 2 9.8 2.1 (cos 30 - cos 60)
v² = 41.16 0.366
v = 3.88 m / s
In conclusion using the conservation of mechanical energy we can find the result for the speed of the pendulum when it is at 30º is:
The speed is: 3.88 m / s
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Answer:
3.0 J
Explanation:
Just took the test
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I suspect you are more concerned with the PERIOD of the swing rather than what is superior to it. (How would one even compare?)
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Question 2 of 10
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Answers
In order to calculate frictional force look below..
The formula given by
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Or
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Answers
The time taken for the light to travel from the camera to someone standing 7 m away is 2.33×10¯⁸ s
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A__________ shows how velocity changes over time
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Answer:
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Answers
The velocity of the rock after 2s is 12.56 m/s.
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The velocity of the rock at 25 m downwards is -15.97 m/s.
The given parameters;
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[tex]v = \frac{dh}{dt}= 20 -2(1.86)t \\\\v = 20 - 3.72t\\\\at \ t= 2 \ s \\\\v = 20 - 3.72(2) = 12.56 \ m/s[/tex]
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The velocity of the rock at 25 m downwards (t = 9.67 s) is calculated as;
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The linear speed of the hummingbird is calculated as follows;
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The centripetal acceleration of the hummingbird is calculated as follows;
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I hope I've helped! :)
Mr. Jones's prescription calls for 1.04 tablets per day. Based on this information, he should take 1 tablet per day. The correct option is C.
What is prescription?The doctor suggests the medicine to be taken by the patient for the treatment of any disease or symptom is called as prescription.
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No one can consume .04 of a tablet, we can round off 1.04 to 1. This means that Mr. Jones should take 1 tablet per day.
Thus, the correct option is C.
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Answers
Answer:
Explanation:
ake is 1.2 x 10^12 J. Only 6.2 x 10^11 J of electrical energy is generated when the water is released. Calculate the efficiency of this energy
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A simple device used for spinning is a hand spindle also known as takli.
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Answers
The coefficient of kinetic friction for the rough horizontal surface is 0.66.
The given parameters;
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[tex]F_kd_1 = \frac{1}{2} kd_2^2\\\\\mu_kmg cos(\theta)d_1 = \frac{1}{2} kd_2^2\\\\\mu_k(1 \times 9.8 \times cos(30)\times 4) = \frac{1}{2} \times 26.5 \times (1.3)^2\\\\33.95\mu_k = 22.39\\\\\mu_k = \frac{22.39}{33.95} \\\\\mu_k = 0.66[/tex]
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Answer:
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