In this problem, you will use your prior knowledge to derive one of the most important relationships in mechanics: the work-ener
1 answer:
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Answer:
The answer is "-72 k".
Explanation:
Please find the complete question in the attached file.
Given point:
Calculating the area:
Answer:
Approximately .
Explanation:
<h3>Solve this question with a speed-time plot</h3>The skateboarder started with an initial speed of and came to a stop when her speed became
. How much time would that take if her acceleration is
?
.
Refer to the speed-time graph in the diagram attached. This diagram shows the velocity-time plot of this skateboarder between the time she reached the incline and the time when she came to a stop. This plot, along with the vertical speed axis and the horizontal time axis, form a triangle. The area of this triangle should be equal to the distance that the skateboarder travelled while she was moving up this incline until she came to a stop. For this particular question, that area is approximately equal to:
.
In other words, the skateboarder travelled up the slope until she came to a stop.
A more general equation for this kind of motion is:
,
where:
and
are the initial and final velocity of the object,
is the constant acceleration that changed the velocity of this object from
is the distance that this object travelled while its velocity changed from
For the skateboarder in this question:
.
Stephen`s Law:
P = (Sigma) · A · e · T^4
P in = P out
e = 1 for blacktop;
1150 W = (Sigma) · T^4
(Sigma) = 5.669 · 10 ^(-8) W/m²K^4
T^4 = 1150 : ( 5.669 · 10^(-8) )
T^4 = 202.875 · 10^8
![T = \sqrt[4]{202.857 * 10 ^{8} }](https://tex.z-dn.net/?f=T%20%3D%20%20%5Csqrt%5B4%5D%7B202.857%20%2A%2010%20%5E%7B8%7D%20%7D%20)
T = 3.774 · 10² = 377.4 K
Answer: Equilibrium temperature is 377.4 K.
P = (Sigma) · A · e · T^4
P in = P out
e = 1 for blacktop;
1150 W = (Sigma) · T^4
(Sigma) = 5.669 · 10 ^(-8) W/m²K^4
T^4 = 1150 : ( 5.669 · 10^(-8) )
T^4 = 202.875 · 10^8
T = 3.774 · 10² = 377.4 K
Answer: Equilibrium temperature is 377.4 K.