+0  
 
+5
515
1
avatar

A machine bales recycled goods into bales measuring 5ft by 4ft by 3ft.

a) a new machine is beign considered that will make right cylindrical bales. If the bales contain the same amount of materal as the original ones and have a height of 5ft, what is their diameter?

b) Which type of bale has a smaller surface area? Justify your answer

 Oct 18, 2015
 #1
avatar+130536 
+5

A machine bales recycled goods into bales measuring 5ft by 4ft by 3ft.

a) a new machine is beign considered that will make right cylindrical bales. If the bales contain the same amount of materal as the original ones and have a height of 5ft, what is their diameter?

b) Which type of bale has a smaller surface area? Justify your answer

 

a) The volume  of each bale produced by the first baler is   60ft^3

 

Vcylinder  = pi r^2 * h    ....so we have

 

60ft^3 = pi * r^2 * 5ft

 

[60 ft^3] / [ 5 pi ft  ]   = r^2       take the square root of each side

 

r ≈ 1.95 ft  so the diameter ≈ 3.90 ft

 

b)  the surface area of the first bale = 2 [20 + 15 + 12]  = 2 [ 47]  = 94 ft^2

 

The surface area of the cylindrical bale = 2pi * r (r + h)   = 2pi* 1.95 (1.95 + 5) ≈  85.15 ft^2

 

So....the cylindrical bale has the smaller surface area......

 

 

cool cool cool

 Oct 18, 2015

2 Online Users

avatar