Why do you weigh about 0.5% less at the equator than at the pole?
Show answer & explanation
Answer: Earth's spin flings you out; the equator bulges farther out
Earth's spin flings you out; the equator bulges farther out ✓ — Correct! Two effects combine. About 70% is centrifugal: Earth's spin flings you outward at the equator, and there's no such fling at the poles. The other 30% is Earth's bulge — the equator is about 21 km farther from the center of mass than the poles. Both thin out local gravity.
The equator is closer to the Sun, cancelling some gravity — Not quite. The Sun is 150 million km away; the extra 12,000 km between the far side of Earth and the Sun is a rounding-error distance. Solar gravity on your body is already a billion times weaker than Earth's, and overhead vs underfoot makes no practical difference.
Polar magnetic field is stronger and presses you down — Not quite. Earth's magnetic field doesn't meaningfully pull on your body — you're not ferromagnetic enough. The field is slightly stronger near the poles, but it's measured in microteslas and has no effect on weight.
More Physics in Daily Life questions
- In a warm office that already reads 26 C, which change can make people feel cooler without lowering the thermostat?
- Why might 26 C feel acceptable in a breezy naturally ventilated summer building but too warm in a sealed winter office?
- On a warm humid day, why can the same 27 C room feel much worse once you start sweating?
- Why can moving air make a 27 C room feel cooler without changing the thermometer?
- Which hidden factor can make a desk beside a cold window feel chilly even when the thermostat across the room still reads 22 C?
- In the same 22 C room, why might someone who just climbed stairs feel warm while someone sitting in a T-shirt feels chilly?