The Bridge and the Rock Using energy considerations and assuming negligible air resistance, find the speed of a rock just before it hits the water if it is thrown from a bridge 16.4 m above water with an initial speed of 16.4 m/s? (Verify that the speed is independent of the direction the rock is thrown.)

24.30 m/s

Explanation:

If the stone is thrown horizontally, our horizontal velocity u₁ = 16.4 m/s and its initial vertical velocity, U = 0 and its final vertical velocity, V is thus

V² = u² + 2gs   where s = height of bridge above water = 16.4 m, g = 9.8 m/s²

v² = 0 + 2 × 9.8 × 16.4 = 321.44

v = √321.44 = 17.93 m/s

Since the horizontal velocity is constant, our resultant velocity just before it hits the water is v₁ = √(u₁² + v²) = √(16.4² + 17.93²) = √(268.96 + 321.44) = √590.4 = 24.30 m/s

If the stone is thrown vertically, its initial vertical velocity, u = 16.4 m/s. its final vertical velocity, v is thus

V² = u² + 2gs   where s = height of bridge above water = 16.4 m

v² = 16.4² + 2 × 9.8 × 16.4 = √(268.96 + 321.44)

v = √590.4 = 24.30 m/s

  the grams     of oxygen gas   that can be produced     is 20.6   grams of o₂

calculation

2liclo₃ →   2 licl + 3 o₂

step 1:   find the moles of liclo₃

moles = mass÷ molar mass

from periodic table the molar mass of liclo₃ =6.9 +35.5   +(16 x3) =90.4 g/mol

moles=38.7 g÷90.4 g/mol=0.4281   moles

step 2:   use the   mole ratio   to calculate the moles of o2

from equation above, liclo₃: o₂   is 2: 3  

therefore the moles of   o₂=0.4281 moles x3/2 =0.6422   moles

step 3: find mass   of o₂

mass= moles x molar mass

from periodic table the   molar mass of   o₂ = 16 x2= 32 g/mol

mass=0.6422   moles   x   32 g/mol = 20.6 grams of o₂

get the total number of pieces of fruit and divide it by 4 to get the average. the result is the answer to the problem. 14 total number of fruits and there are 4 members. 14 divided by 4 is equals to 3.5.