Math Problem Statement

a spherical ball is immersed in water contained in a vertical cylinder. the rise in water level is measured in order to calculate the radius of the spherical ball. calculate the radius of the ball in the following cases : cylider of radius 10 cm, water level rises 4cm

Solution

To calculate the radius of the spherical ball based on the rise in water level, we need to equate the volume of the displaced water to the volume of the spherical ball. Here's how we can calculate it:

Given:

  • Radius of the cylinder R=10cmR = 10 \, \text{cm}
  • Rise in water level h=4cmh = 4 \, \text{cm}

Step 1: Volume of water displaced

The volume of water displaced is equal to the volume of the cylinder that corresponds to the rise in water level. This is given by the formula for the volume of a cylinder:

Vwater=πR2hV_{\text{water}} = \pi R^2 h

Substituting the known values:

Vwater=π(10cm)2(4cm)=400πcm3V_{\text{water}} = \pi (10 \, \text{cm})^2 (4 \, \text{cm}) = 400 \pi \, \text{cm}^3

Step 2: Volume of the spherical ball

The volume of the spherical ball is given by the formula:

Vball=43πr3V_{\text{ball}} = \frac{4}{3} \pi r^3

Where rr is the radius of the ball. Since the ball displaces an equal amount of water, we set the volume of the ball equal to the volume of the water displaced:

43πr3=400π\frac{4}{3} \pi r^3 = 400 \pi

Step 3: Solve for the radius rr

Cancel out π\pi on both sides of the equation:

43r3=400\frac{4}{3} r^3 = 400

Multiply both sides by 34\frac{3}{4}:

r3=34×400=300r^3 = \frac{3}{4} \times 400 = 300

Now, take the cube root of both sides:

r=3003r = \sqrt[3]{300}

Using the cube root:

r6.67cmr \approx 6.67 \, \text{cm}

Final Answer:

The radius of the spherical ball is approximately 6.67 cm.


Would you like more details or have any further questions?

Here are 5 related questions to expand your understanding:

  1. How do you calculate the volume of a cylinder with different dimensions?
  2. What happens if the cylinder is not perfectly vertical?
  3. How does the formula for a sphere's volume differ from other geometric shapes?
  4. If the water level rises by 8 cm instead of 4 cm, how would the radius change?
  5. How does the density of the ball affect the water displacement?

Tip: Whenever working with volumes in geometry, remember that displacement principles allow you to calculate complex shapes through simpler measurements, like water levels!

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Math Problem Analysis

Mathematical Concepts

Geometry
Volume Displacement
Spherical Volume Calculation

Formulas

Volume of a Cylinder: V = πR²h
Volume of a Sphere: V = (4/3)πr³

Theorems

Archimedes' Principle (Displacement)

Suitable Grade Level

Grades 9-12