Two train cars moving in the same direction are going to be coupled together. The mass of the first car is 5,000 kg and is moving at 5 m/s; the second car weighs the same, but is moving at 1 m/s. How fast will the two coupled cars move and how much kinetic energy does the system lose from coupling the cars together after they collide

Explanation:

Given

Mass of the first car

Mass of the second car

The velocity of the first car is

The velocity of the second car is

Conserving momentum, take as the velocity after coupling

  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

watch you tube or play clash royale, mainly clash royale