An astronaut is floating in space when the support line is cut. if the 68kg astronaut needs to reach the spaceship (20m away), how long will it take if he throws a 12kg canister at 12m/s?

9.43 s

Explanation:

Since there is no external force acting in space, the total momentum of the entire system would be conserved.

When the astronaut throws a canister, an equal and opposite amount of force would act on the astronaut which means momentum of the canister would be equal to momentum of the astronaut,

⇒ m v = m' v'

⇒ 12 kg × 12 m/s = 68 kg × v'

The velocity of the astronaut would be:

v' = 2.12 m/s

The distance need to be covered by astronaut to reach the spaceship = 20 m

Time taken : Distance/ velocity = 20 m / 2.12 m/s = 9.43 s.

Hence, astronaut would take 9.43 s to reach the spaceship.

answer: he got 23

explanation:

  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