The Amway Center in Orlando is approximately 55n (180ft) tall. How fast (speed) will a ball dropped from it's rooftop hit the pavement below? I need help badly

What is the acceleration of a spaceship that is initially at rest and then speeds up to 220 m/s in 20 seconds

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.

If anyone who can me with this hw? i would really appreciate it