4. Assume the earth is a prefect sphere with uniform density and the radius is 6400 km. What is the difference of gravitational acceleration at equator and at north pole?
(A)0.017 m/s²,
(B) 0.034 m/s²,
(C) 0.17 m/s²,
(D) 0.34 m/s².

1. 題目解析這道題目要求我們計算地球...