An object is dropped onto the moon (g m = 5 ft/s 2 ). how long does it take to fall from an elevation of 250 ft.?

To determine the time needed in order for the object to reach a certain elevation we use the equation,
 
   d = V₀t + 1/2(gt²)

where d is the distance,
V₀ is the initial velocity which is equal to zero because the object is simply dropped
g is the acceleration due to gravity, and 
t is the time

If we derive the equation in order to solve for t, we have,
 
     t = sqrt ((2d/g))

If we convert the given in SI units,
   d = (250 ft) x (0.3048 m/ 1 ft) = 76.2 m
   g  = (5 ft/s²)(0.3048 m/ 1 ft) = 1.524 m/s²

Substitute,
 
      t = sqrt ((2)(76.2 m)/(1.524 m/s²))
      t = 10 s

Therefore, it will take 10 s for the object to be dropped to a distance of 250 ft. 

the catch is that the top numbers are atomic masses the bottom numbers are the numbers of protons and electrons in an uncharged atom. they are the number of that atoms as you would find them on the periodic table. further, the numbers on the left are used to determine the missing numbers on the right

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer