During a lunar mission, it is necessary to increase the speed of a spacecraft by 2.1 m/s when it is moving at 370 m/s relative to the moon. the speed of the exhaust products from the rocket engine is 1200 m/s relative to the spacecraft. what fraction of the initial mass of the spacecraft must be burned and ejected to accomplish the speed increase?

Why does lightning travel from clouds to the ground? a. the negatively charged ground attracts the positive charge from the clouds b. charges are exchanged between negatively charged clouds and positively charged ground c. gravity pulls the negatively charged energy from clouds downward d. gravity pulls the positively charged energy from clouds downward