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.