A spiral staircase in a building is in the shape of a helix of radius meters. Between two floors of the building, the stairs make one full revolution and climb by meters. A person carries a bag of groceries up two floors. The combined mass of the person and the groceries is kg and the gravitational force is downward, where is the acceleration due to gravity, in meters per second squared. Calculate the work done by the person against gravity in joules. Enter the exact answer.

-5488 J

Explanation:

The work done by the person against gravity is equal to the change in gravitational potential energy.

Therefore we can write:

where

m is the combined mass of the man + groceries

g is the acceleration due to gravity

is the change in height

In this problem we have:

m = 70 kg is the combined mass of the man + groceries

is the acceleration due to gravity

, since the man climbed down 2 floors and each floor is 4 meters

Therefore, the work done against gravity is

  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