A skier with a 65kg mass skies down a 30 degree incline hill. The coefficient of friction is 0.1. a. Draw a free body diagram. b
1 answer:
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Answer:
- It can be infer that it has a lower frequency.
<em>In the case of electromagnetic waves.</em>
- A short wavelength means a lower energy,
Explanation:
The wavelength is the distance between two consecutive crests or valleys while the frequency is the number of crests that pass for a specific point in an interval of time.
For example, a person makes laundry once a weak.
In this example, the event is represented by the laundry and the interval of time is once a weak
The velocity of a wave is defined as:
(1)
Where is the frequency and
is the wavelenth
(2)
Notice from equation 2 that the wavelength is inversely proportional to the frequency (when the wavelength increases the frequency decreases).
In the case of electromagnetic waves, a short wavelength means a lower energy, as it can be seen in equation 4 (inversely proportional).
(3)
(4)
Answer:
Uk = 9.9 J
Explanation:
To calculate the kinetic energie (Uk), you can make use of this formula:
Uk = 0.5 * m * v²
given m = 55 kg and v = 0.6 m/s
Substituting in the formula gives:
Uk = 0.5 * 55 * (0.6)²
Uk = 0.5 * 55 * 0.36
Uk = 9.9 J
Extra:
Now let's examine the formula in relation to the SI units. <em>If you understand the following, it will give you great insight in how smart Phisics is inter twained by looking at formulas and their standard units. It will save you time in future to convert formulas, if you use the right standard units.</em>
The formula for kinetic energie is:
Uk = 0.5 * m * v²
Standard SI unit for mass m is kg.
Standard SI unit for speed v is m/s.
So v * v = v² and therefore v² must have the standard SI unit of m²/s².
From the formula, you see that the unit of Uk must be kg*m²/s² and since Uk is normally given in J, these both forms must be the same !
The main unit for Uk is the Joule. <em>Now</em><em> </em><em>please</em><em> </em><em>see</em><em> </em><em>the</em><em> </em><em>picture</em><em>,</em><em> </em><em>which</em><em> </em><em>shows</em><em> </em><em>the </em><em>relation</em><em> </em><em>between </em><em>the </em><em>J </em><em>and </em><em>other</em><em> SI units</em><em>.</em><em> </em><em>Please</em><em> </em><em>understand</em><em> </em><em>that</em><em> </em><em>you</em><em> </em><em>can</em><em> </em><em>construct</em><em> </em><em>your</em><em> </em><em>'own'</em><em> </em><em>formulas</em><em> </em><em>based</em><em> </em><em>these</em><em> </em><em>units</em><em>.</em><em> </em><em>Now</em><em> </em><em>here</em><em> </em><em>is</em><em> </em><em>the</em><em> </em><em>time</em><em> </em><em>saver</em><em>:</em>
Because almost always the right units are <em>given</em> in a question, or because sometimes you can look up a constant in a table with an exotic and seemingly complicated unit, but that says a lot about the formula which must have been some how involved!
<em>By this, I hope you now understand the implication of using the right standard SI units and how that can help you figure out what formula is needed.</em>
Answer:
0.906
Explanation:
Let g = 9.81 m/s2. We can calculate the rate of change in potential energy when m = 201kg of water is falling down a distance of h = 131m per second
So the efficiency of the water turbine is the ratio of output power over input power: