New streetlights will be installed along a section of the highway. The posts for the streetlights will

be 7.5 m tall and made of aluminum. The city can choose to buy the posts shaped like cylinders or

the posts shaped like rectangular prisms.

The cylindrical posts have a hollow core, with aluminum 2.5 cm thick, and an outer diameter of

53.4 cm. The rectangular-prism posts have a hollow core, with aluminum 2.5 cm thick, and a

square base that measures 40 cm on each side.

The density of aluminum is 2.7 g/cm3, and the cost of aluminum is $0.38 per kilogram.

a) What is the cost of the cylindrical posts, to the nearest cent?

b) What is the cost of the rectangular-prism posts, to the nearest cent?

  1. 👍
  2. 👎
  3. 👁
  1. cylinder: π/4 * (53.4^2 - (53.4-5)^2) * 750 cm^3 * 2.7 g/cm^3 * 1kg/1000g * $0.38/kg = $307.62
    prism: (40-5)^2 * 750 cm^3 * 2.7 g/cm^3 * 1kg/1000g * $0.38/kg = $942.64

    1. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions

  1. Math

    Suppose that the amount of time it takes to build a highway varies directly with the length of the highway and inversely with the number of workers. Suppose also that it takes 100 workers 6 weeks to build 4 miles of highway. How

  2. Math

    Select the cross-section that results from slicing a rectangular pyramid. The pyramid is sliced in a way such that the plane passes through the middle of the pyramid in a direction perpendicular to the base. A. The cross-section

  3. physics

    how much will the length of a 1.0 km section of concrete highway change if the temperature varies from -15 Celsius in the winter to 41 Celsius in the summer?

  4. math

    Tom built a fence around his rectangular shaped pool. The posts are 2 yards apart, there are 4 posts along the width and 8 posts along the length. What are the dimensions of the fence?

  1. To tutors

    This website is good but there is a problem. You can ban people from this website and delete posts. CAN YOU PLEASE STOP BANNING PEOPLE?! IT TAKES LIKE WEEKS TO GET BANNED FROM JISKHA. Also STOP DELETING POSTS! IT IS REALLY

  2. physics

    A steel section of the Alaskan pipeline had a length of 65 m and a temperature of 22° C when it was installed. What is its change in length when the temperature drops to a frigid -37° C?

  3. Math

    How many posts does it take to support a fence around a square field measuring 200ft on a side if posts are placed every 20ft

  4. Math

    A stadium has two sections Tickets for section A cost $a each Tickets for Section B cost $b each Johanna paid $105 for 5 section A tickets and 3 section B tickets. Raiyah Paid $63 for 4 section A tickets and 1 section B ticket

  1. Microeconomics

    which of the following situations describes an equilibrium? which does not? if the situation does not describe an eqilibrium, what would an eqilibrium look like? a. many people regularly commute from the suburbs to downtown

  2. Music

    In a Baroque da capo movement, it is customary to improvise ornaments during which section? A) The first A section. B) The B section C.) The second A section D) none of the above

  3. Geometry Part 2

    A highway makes an angle of 6 with the horizontal.This angle is maintained for a horizontal distance of 5 miles.To the nearest hundredth of a mile, how high does the highway rise in this 5- mile section?Show the steps you use to

  4. microeconomic

    12. In each of the following situations, explain how government intervention could improve society’s welfare by changing people’s incentives. In what sense is the market going wrong? a. Pollution from auto emissions has

You can view more similar questions or ask a new question.