Solve the each given problem:
Problem I: How much energy is required to accelerate a spaceship with a rest mass of 105 metric tons to a speed of 0.469 c?
Problem II: Every day our Earth receives 1.55×1022 J energy from the Sun. If we were able to use 0.75 percent of this energy to accelerate spaceships, then how many missions would be possible in one year?
I want you to explain the physics in this above problems. Thanks.