A. a puck hovers and glides across an air track at constant velocity.

b. a dishwasher was pulled up to a window by a rope using a pulley system.

c. a feather falls from one end of a tube to the other inside a vacuum.

d. a charged particle was pushed away by another charged particle.

Option C

A feather falls from one end of a tube to the other inside a vacuum

Explanation:

In conservative force field, which in this case is a vacuum, you expect that there will be no loss of energy to air-friction. Therefore, when a feather falls from one end of the tube to the other side which is a vacuum, we expect no energy loss. Conservative forces are the forces that are path-independent. This implies that in a closed loop, the total work done is zero. Considering the options given, only feather falls from one end of a tube to the other inside a vacuum meets the criteria

the diagram which shows forces as either balanced = same speed or unbalanced = accelerarting

  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