In the picture below, half of Earth is experiencing day, and half is experiencing night. If the Sun is always giving off light, why do we not all experience day all the time? In your own words, explain why we have a cycle of light and dark that repeats every 24 hours in most parts of the world.

The man of mass m1 and the woman of mass m2 are standing on opposite ends of the platform of mass m0 which moves with negligible friction and is initially at rest with s = 0. the man and woman begin to approach each other. derive an expression for the displacement s of the platform when the two meet in terms of the displacement x1 of the man relative to the platform.