Jack drops a stone from rest off of the top of a bridge that is 21.2 m above the ground. After the stone falls 6.6 m, Jill throws a second stone straight down. Both rocks hit the water at the exact same time. What was the initial velocity of Jill's rock

11.4 m/s

Explanation:

Given that Jack drops a stone from rest off of the top of a bridge that is 21.2 m above the ground. After the stone falls 6.6 m, Jill throws a second stone straight down.

Since Both rocks hit the water at the exact same time, The final velocity V of Jack stone will be:

V^2 = U^2 + 2gH

Since the stone was dropped from rest, U = 0

V^2 = 2 × 9.8 × 21.2

V^2 = 415.52

V = 20.4 m/s

the initial velocity of Jill's rock will be found by using the same formula. Assuming that they both have the same final velocity V

V^2 = U^2 + 2gH

20.38^2 = U^2 + 2 × 9.8 × ( 21.2 - 6.6 )

415.52 = U^2 + 19.6 × 14.6

415.52 = U^2 + 286.16

U^2 = 415.52 - 286.16

U^2 = 129.36

U = 11.3736 m/s

Therefore, the initial velocity of Jill's rock is 11.4 m/s approximately

some think that theories become laws, but theories and laws have separate and distinct roles in the scientific method. a law is a description of an observed phenomenon in the natural world that hold true every time it is tested. it doesn't explain why something is true; it just states that it is true.

  the unit of the measure =

explanation:

  the property that is quantified by the energy needed per of material to raise the temperature by one.

  si unit of energy = joule (j)

  si unit of temperature = kelvin (k)

  si unit of mass of material = kilogram (kg)

the property that is quantified by the energy needed per of material to raise the temperature by one is called specific heat.

the unit of specific heat is