Math Problem Statement

A body is at rest at a location on the Earth’s equator. Find its acceleration due to the Earth’s rotation. (Take the Earth’s radius at the equator to be 6400 km.)

Solution

To find the acceleration due to the Earth's rotation at the equator, we need to use the formula for centripetal acceleration, which arises from the rotational motion of an object moving in a circle:

a=ω2ra = \omega^2 r

where:

  • aa is the centripetal acceleration,
  • ω\omega is the angular velocity of the Earth,
  • rr is the radius of the Earth at the equator.

Step 1: Find the angular velocity (ω\omega) of the Earth

The Earth completes one full rotation in 24 hours, which is equivalent to 8640086400 seconds. The angular velocity is given by:

ω=2πT\omega = \frac{2\pi}{T}

where TT is the period of rotation (24 hours = 86400 seconds). Thus,

ω=2π86400rad/s\omega = \frac{2\pi}{86400} \, \text{rad/s}

Step 2: Convert the Earth's radius to meters

Given that the radius rr at the equator is 6400km6400 \, \text{km}, we convert it to meters:

r=6400×103m=6.4×106mr = 6400 \times 10^3 \, \text{m} = 6.4 \times 10^6 \, \text{m}

Step 3: Calculate the centripetal acceleration

Now we can substitute the values of ω\omega and rr into the centripetal acceleration formula:

a=(2π86400)2×6.4×106a = \left( \frac{2\pi}{86400} \right)^2 \times 6.4 \times 10^6

Let’s calculate this.

ω=2π864007.272×105rad/s\omega = \frac{2\pi}{86400} \approx 7.272 \times 10^{-5} \, \text{rad/s}

a=(7.272×105)2×6.4×1060.034m/s2a = (7.272 \times 10^{-5})^2 \times 6.4 \times 10^6 \approx 0.034 \, \text{m/s}^2

Final Answer:

The acceleration due to the Earth's rotation at the equator is approximately 0.034 m/s².


Would you like more details on the steps, or do you have any questions?

Here are 5 related questions you might find interesting:

  1. How would the acceleration change if we were at the North Pole instead of the equator?
  2. What factors affect the centripetal acceleration at the equator?
  3. How does the acceleration due to Earth's rotation compare to gravity at the equator?
  4. What would happen to the centripetal acceleration if the Earth rotated faster?
  5. How do you derive the formula for centripetal acceleration from Newton’s laws?

Tip: The Earth’s rotation is much slower than objects you might encounter in daily life (like a car turning a corner), so the centripetal acceleration due to the Earth's rotation is small in comparison.

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Math Problem Analysis

Mathematical Concepts

Centripetal Acceleration
Rotational Motion
Angular Velocity
Unit Conversion

Formulas

a = ω^2 r
ω = 2π / T

Theorems

Centripetal acceleration theorem
Earth's rotation and angular velocity relation

Suitable Grade Level

Grades 9-11