Please help I will mark as brainliest

dem82 [27]

Time taken is equal to distance divided by speed
So time is 50/5 = 10 seconds

5 0

3 years ago

A cylindrical can without a top is made to contain 25 3 cm of liquid. What are the dimensions of the can that will minimize the

Basile [38]

Answer:

Therefore the radius of the can is 1.71 cm and height of the can is 2.72 cm.

Step-by-step explanation:

Given that, the volume of cylindrical can with out top is 25 cm³.

Consider the height of the can be h and radius be r.

The volume of the can is V= $\pi r^2h$

According to the problem,

$\pi r^2 h=25$

$\Rightarrow h=\frac{25}{\pi r^2}$

The surface area of the base of the can is = $\pi r^2$

The metal for the bottom will cost $2.00 per cm²

The metal cost for the base is =$(2.00× $\pi r^2$ )

The lateral surface area of the can is = $2\pi rh$

The metal for the side will cost $1.25 per cm²

The metal cost for the base is =$(1.25× $2\pi rh$ )

$=\$2.5 \pi r h$

Total cost of metal is C= 2.00 $\pi r^2$ + $2.5 \pi r h$

Putting $h=\frac{25}{\pi r^2}$

$\therefore C=2\pi r^2+2.5 \pi r \times \frac{25}{\pi r^2}$

$\Rightarrow C=2\pi r^2+ \frac{62.5}{ r}$

Differentiating with respect to r

$C'=4\pi r- \frac{62.5}{ r^2}$

Again differentiating with respect to r

$C''=4\pi + \frac{125}{ r^3}$

To find the minimize cost, we set C'=0

$4\pi r- \frac{62.5}{ r^2}=0$

$\Rightarrow 4\pi r=\frac{62.5}{ r^2}$

$\Rightarrow r^3=\frac{62.5}{ 4\pi}$

⇒r=1.71

Now,

$\left C''\right|_{x=1.71}=4\pi +\frac{125}{1.71^3}>0$

When r=1.71 cm, the metal cost will be minimum.

Therefore,

$h=\frac{25}{\pi\times 1.71^2}$

⇒h=2.72 cm

Therefore the radius of the can is 1.71 cm and height of the can is 2.72 cm.

6 0

3 years ago

Problem of the Week

Ierofanga [76]

Answer:

CD is 6 cm and DE is 4 cm.

Step-by-step explanation:

Well it‘s the correct answer and I got it right so good luck out there bois!

6 0

2 years ago

I thought it was 25/100 buts it’s wrong

viva [34]

Answer:

Step-by-step explanation:

a to b represents a quarter of the line segment in order to get to %100 we need to multiply 2in by 4.

2x4=8

4 0

3 years ago

Using the solubility curve, choose all of the statements that are correct.

irinina [24]

Answer:

See explanation below

Step-by-step explanation:

According to the solubility curve attached, let's analyze each sentence to see which one is correct:

"Solubility of NaCl is least affected by temperature"

True. as you can see in the curve, solubility of NaCl remains almost constant at any value of temperature, so in this case, it does not matter the temperature, the NaCl solubility will be the same.

"completely dissolve 60 g of KBr in 100 g of water at 20 °C"

True. As you can see in the graph, solubility of KBr begins at 60 g, so in 20 °C we have something dissolved there. Actually you have like 70 g dissolved there, so, this is true.

"The solubility of KNO3 is the least affected by changes in temperature"

False. The curve for KNO3 is exponencial, so, changes in temperature do actually affect the solubility.

"100 g of KBr will dissolve completely in 100 g of water at 75 °C"

False. According to the curve, 100 g dissolve when we reach more than 100 °C. At 75 °C only about 85 g of KBr is dissolved.

"if you mix 120 g of NaClO3 in 100 g of water at 10 °C, approximately 30 g will not dissolve"

True. In the graph we can clearly see that at 10 °C only about 90 g is being dissolved so, the rest of the mass is still there as mass.

6 0

2 years ago