Assignment:
The solar wind is a continuous stream of particles, mostly protons and electrons, moving away from the Sun. When the particles encounter Earth's upper atmosphere, they are moving at speeds of several hundred km/s. If such a particle reaches Earth's upper atmosphere with a speed of 92 km/s, how fast was it moving when it crossed Mercury's orbit at a distance of 5.8 ´ 107 km from the Sun? (HINT: Assume that the particles are slowed by the Sun's gravitational field as they move away from the Sun and ignore any increase the particles experience from the Earth's gravitational force.)
Provide complete and step by step solution for the question, use formulas.