A student wants to launch a tennis ball horizontally just over a 6.0 m high fence and have it land at approximately 20.0 m beyond the fence. What speed would the tennis ball need to have to land at this approximate distance?

Explanation:

Time taken for vertical displacement will be equal to time taken for horizontal displacement .

Let it be t

for vertical fall , initial velocity u = 0

h = ut + 1/2 gt²

6 = 0 + .5 x 9.8 t²

t = 1.1065 s

horizontal displacement = horizontal velocity x time

20 = horizontal velocity x 1.1065

horizontal velocity = 18 m /s approx.

  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

the force represented by vector a is normal force. if the hockey puck is moving to the right, when it is hit with a significant force by the hockey stick the puck will move off in a different direction. correct on edge.