Effect of altitude on electronic balance. If an object weighs ma grams at distance ra from the

Question:

Effect of altitude on electronic balance. If an object weighs ma grams at distance ra from the center of the Earth, it will weigh mb = ma(r2a/r2b) when raised to rb. An object weighs 100.0000 g on the first floor of a building at ra = 6370 km. How much will it weigh on the tenth floor, which is 30 m higher?