Sputnik I Was Launched into Orbit Around Earth in 1957

Multiple Choice

Sputnik I was launched into orbit around Earth in 1957.It had a perigee (the closest approach to Earth,measured from Earth's center) of 6.81 × 10⁶ m and an apogee (the furthest point from Earth's center) of 7.53 × 10⁶ m.What was its speed when it was at its perigee? The mass of Earth is 5.97 × 10²⁴ kg and G = 6.67 × 10^-11 N ∙ m²/kg².

A) 7180 m/s
B) 7840 m/s
C) 8230 m/s
D) 11,000 m/s
E) 13,400 m/s