a marbel is thrown vertically upward with some initial speed from a atall building.?

Question

At the instant that it passes its initial position on its way down, a heavier marble is thrown verticaly downward from the same initial speed. which marble reach the ground first (neglect air friction)? why?

Answer 1

They will hit the ground at the same time disregarding air friction because Galileo proved that two objects dropped from the same height will reach the ground at the same time.

Answer 2

Both hit the ground at the same time. The first marble returns to its starting point traveling at the same speed but moving down. You can prove this simply enough - use conservation of energy or use

y = (v^2-v0^2)/(2g) where v0 = starting speed, v = speed after traveling displacement y, g = acceleration due to gravity.

The first marble experiences zero displacement over the time it is tossed upward and returns back to the height it was tossed from. So then v = v0. Since the second marble is tossed downward at the same speed when the first marble returns, they both hitthe ground at the same time.

Answer 3

They'll hit the ground at the same time. The velocity of the smaller marble will be at the same intial velocity when it passes by the starting point.

Answer 4

the first marble because it was thrown up then down so it picked up speed and the higher it falls from the faster it'll fall?

Answer 5

same time because the acceleration of gravity is constant

can be seen when dropping a bowling ball and feather
they hit at the same time because they have the same verticle distance component, same time to fall that distance, and same acceleration (aka gravity, which is constant)