Gravitational Potential Energy: a Meteoroid, Heading Straight for Earth, Has

Multiple Choice

Gravitational potential energy: A meteoroid, heading straight for Earth, has a speed of 14.8 km/s relative to the center of Earth as it crosses our moon's orbit, a distance of 3.84 × 10⁸ m from the earth's center. What is the meteroid's speed as it hits the earth? You can neglect the effects of the moon, Earth's atmosphere, and any motion of the earth. (G = 6.67 × 10^-11 N ∙ m²/kg², M_earth = 5.97 × 10²⁴ kg)

A) 18.5 km/s
B) 21.5 km/s
C) 32.4 km/s
D) 87.3 km/s