find the capacity on letres of a bucket 2cmin diameter at the top, 16cm in diameter at the bottom and 20cm deep

1 answer

To find the capacity of the bucket in liters, we can model the bucket as a frustum of a cone (a cone with the top part cut off). The formula for the volume \( V \) of a frustum is given by:

\[ V = \frac{1}{3} \pi h (r_1^2 + r_2^2 + r_1 r_2) \]

where:

  • \( h \) is the height of the frustum,
  • \( r_1 \) is the radius of the top base,
  • \( r_2 \) is the radius of the bottom base.

Step 1: Convert dimensions to radius and height

  • The diameter at the top is 12 cm, so the radius \( r_1 = \frac{12}{2} = 6 \) cm.
  • The diameter at the bottom is 16 cm, so the radius \( r_2 = \frac{16}{2} = 8 \) cm.
  • The height of the bucket \( h = 20 \) cm.

Step 2: Plug values into the formula

Now we can substitute these values into the volume formula:

\[ V = \frac{1}{3} \pi (20) (6^2 + 8^2 + 6 \cdot 8) \]

Calculating the squares and the product:

\[ 6^2 = 36, \quad 8^2 = 64, \quad 6 \cdot 8 = 48 \]

Now, substitute these into the equation:

\[ V = \frac{1}{3} \pi (20) (36 + 64 + 48) \]

Calculating inside the parentheses:

\[ 36 + 64 + 48 = 148 \]

Now substitute this back into the volume equation:

\[ V = \frac{1}{3} \pi (20) (148) \]

Calculating:

\[ V = \frac{1}{3} \cdot \pi \cdot 2960 \]

Calculate \( \frac{2960}{3} \):

\[ \frac{2960}{3} \approx 986.67 , \text{cm}^3 \]

Step 3: Convert cubic centimeters to liters

Since 1 liter = 1000 cm³, we convert the volume to liters:

\[ V \approx \frac{986.67}{1000} \approx 0.987 , \text{liters} \]

Final Answer

The capacity of the bucket is approximately 0.987 liters.