In 1986, the first flight around the globe without a single refueling was completed. the aircraft’s average speed was 186 km/h. if the airplane landed at this speed and accelerated at −1.5 m/s2 , how long did it take for the airplane to stop?

34.4 sec

Explanation: Assuming that the desacceleration was constant, we have  a = -1.5m/s²

vi = 186 km/h → 51.6 m/s

vf = 0 (because it stopped)

Vf = Vi + at

0 = 51.6 - 1.5t

1.5t = 51.6

t = 34.4 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

wavelength divides in half and speed stays the same.