Box has all sides same leinght(a). Area of that box is 6*a^2.
Cost of material for bottom and 4 sides is 2$/ft^2. Area of bottom and sides is A=5*a^2
Cost of material for top is 4$/ft^2. Area of top of the box is T=a^2
A*2+T*4=72
5*a^2*2+a^2*4=72
a^2*(10+4)=72
a^2*14=72, a^2=72/14, a=root(72/14), a=2.267ft
Dimensions of the box: leinght of sides 2.2ft. Area of hole box 30.835ft^2
Area of the bottom and sides: A=5*a^2=25.696ft^2
Area of the top : T=a^2=5.139ft^2
Check: A*2$+T*4$=71.95$
Answer:
T1 = 490.5 [N], T2 = 490.5[N]
Explanation:
First, we must draw a free body diagram of the steel ball hanging and the two wires holding it as well as the angle forming the wires between them.
The free-body diagram can be seen in the attached image.
As the cables are symmetrical with respect to the vertical axis, the force in cables 1 and 2 is equal, so when performing a force sum equal to zero on the Y-axis, we can find the force value of any cable.
The solution of the equations can be seen in the attached image
C. Have like poles that repel each other
Answer: mass for Pyrex glass 84.21g
mass for sand 61.6g
mass for ethanol 41.32g
mass for water 62.07g
Explanation
By definition specific heat is the amount of heat required to change the temperature of 1 kg mas by 1°C
Q=mcΔT is formula for specific heat
Q is heat transfer
m is mass
ΔT is change in temperature
c is specific heat
c of Pyrex glass= 0.75 j/g°C
c of sand = 0.84 j/g°C
c of ethanol= 2.42 j/g°C
c of water = 4.18 j/g°C
now we will make M(mass) the subject, so equation becomes
m=Q/cΔT
for
pyrex glass T<em>f=</em>55.4°C
m=1920/(55.4-25)*0.75
m=84.21g {after cutting J(joules) and °C we are left with g(grams)}
for
sand T<em>f</em>=62.1°C
m=1920/(62.1-25)*0.84
m=61.6g {after cutting J(joules) and °C we are left with g(grams)}
for
ethanol T<em>f</em>=44.2°C
m=1920/(44.2-25)*2.42
m=41.32g {after cutting J(joules) and °C we are left with g(grams)}
for
water T<em>f=</em>32.4°
m=1920/(32.4-25)*4.18
m=62.07g {after cutting J(joules) and °C we are left with g(grams)}
i hope you understand the solution, thank you.