Answer: Chapter 3: Bravery.
Explanation: Sal begins the story with her first moments in Lewiston. She overhears Margaret pleading with her father to tell Sal how they met, but Sal rudely refuses to hear the story. Sal marches glumly through their new house, situated only a few blocks from Margaret's, complaining about its size.
Where is the pic for this so I can answer
The expression (PE products) - (PE reactants) represents the heat of reaction for a chemical change in terms of PE (potential energy).
<h3>What is potential energy?</h3>
Potential energy is any type of energy stored to perform physical work in a given period of time.
Conversely, kinetic energy is motion (movement) energy used when performing physical work.
In conclusion, the expression (PE products) - (PE reactants) represents the heat of reaction for a chemical change in terms of PE (potential energy).
Learn more about potential energy here:
brainly.com/question/14427111
#SPJ1
Answer:
A) Cm = 2.232 s/mm²
B) Time taken to solidify = 74.3 seconds
Explanation:
(A) Since a side is 50mm and all sides of a cube are equal, thus, Volume of the cube is;V = 50 x 50 x 50 = 125,000 mm³
There are 6 faces of the cube, thus Surface Area A = 6 x (50 x 50) = 15,000 mm²
So, Volume/Area = (V/A) = 125,000/15,000 = 8.333 mm
Cm is given by the formula; Cm =[Tts] /(V/A)² where Tts is time taken to solidify and it's 155 seconds in the question. Thus;
Cm = 155/(8.333)²= 2.232 s/mm²
(B) For;Cylindrical casting with D = 30 mm and L = 50 mm.;
Volume of cylinder is;
V = (πD²L) /4
So,V = (π x 30² x 50)/4 = 35,343mm³
Surface area of cylinder is;
A = (2πD²)/4 + (πDL)
Thus, A = ((π x 30²)/2) + (π x 30 x 50) = 6126 mm²
Volume/Area is;
V/A = 35,343/6126 = 5.77 mm
Same alloy and mold type was hsed as in a above, thus, Cm is still 2.232 s/mm²
Since Cm =[Tts] /(V/A)²
Making Tts the subject, we have;
Tts =Cm x (V/A)²
Tts = 2.232 x (5.77)² = 74.3 seconds
