Physics problem?

Question

If at 1,000 ft in hight. I drop two objects of the same shape and size. One weights 5 lbs. and the other only 2 lbs.
Which one will reach the ground in less time?
My friend wants to know!!!

Answer 1

a) In vacuum, both will hit ground at the same time.
h = 1/2 gt^2
h = 1000 ft, g = appx 32 ft/s^2
Plugging
t = sqrt[2h/g] = sqrt[2 x 1000 / 32] = 7.91 s

b) Both objects are of same shape (assume spherical) and size. Air resistance will be same for both. Assume air resistance for each of them = 0.25 lbs

Gravitational downpull force on 5 lbs,
F5 = 5 - 0.25 = 4.75 lbs = 4.75 x 32 poundals = (m5)(a5)
m5 = 5 lbs
a5 = 4.75 x 32 / 5 = 30.4 ft/s^2
Time to reach the ground, T5 = sqrt[2 x 1000 / 30.4] = 8.11 s

Gravitational downpull force on 2 lbs,
F2 = 2 - 0.25 = 1.75 lbs = 1.75 x 32 poundals = (m2)(a2)
m2 = 2 lbs
a2 = 1.75 x 32 / 2 = 28.0 ft/s^2
Time to reach the ground, T2 = sqrt[2 x 1000 / 28.0] = 8.45 s

5 lbs object will hit ground (8.45 - 8.11) = 0.34 s earlier than that of 2 lbs object

In free air, 5 lbs object will hit the ground earlier

Answer 2

Theoretically they would hit at the same exact time. But, air resistance must be considered. Since they are the same size and shape, the surface area is the same. So, the air resistance will slow down the 2 lb. ball more than the 5 lb. ball. The 5 lb. ball will hit the ground first.

Answer 3

The 5lb one will hit sooner, because the lighter one will be slowed more by the air resistance.
Without air, both would hit the ground at the same time.

Answer 4

since they are the same shape and size, they will have the same drag coefficient. Therefore, they will hit the ground at the same time.

Answer 5

both balls will hit the ground at the same time. (if air is not involved)