I think by using data collected by Tycho Brahe
Answer:
H = 1/2 g t^2 time to reach top of trajectory
v = g t time to reach top of trajectory when v is initial speed upwards
v = 5 g = 49 m/s 5 sec upwards and 5 sec downwards
Because all objects attract in proportion to the product of their masses.Gravitational interactions exist between all objects with an intensity that is directly proportional to the product of their masses.
