What type of simple machine is a catapult? ( incline plane , lever , pulley , screw , wedge, or a wheel and axle) how do you know ?

Lever

Explanation:

A catapult as a machine is a lever (1st class) because the fulcrum is between the Effort applied and the load(object) to be launched. A first class lever machine is a machine that has the fulcrum in between the effort and the load which makes a catapult a first class lever.

The handle of the catapult is where the effort is applied, the fulcrum is the point of contact between the rubber tied to the stick and the stick itself and the load is the object to be launched.

  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