Calculate the potential energy of a rock that has a 45 kg mass and is sitting
30 m high. use 9.8 m/s ^2 for free-fall acceleration.

P.E = 13230 J

Explanation:

Given,

The mass of the rock, m = 45 Kg

The rock is sitting at a height from the ground, h = 30 m

The acceleration due to gravity, g = 9.8 m/s²

The potential energy of the body is given by the formula,

                            P.E = mgh joules

Substituting the given values in the above equation

                             P.E = 45 x 9.8 x 30

                                   = 13230 J

Hence, the potential energy of the rock is P.E = 13230 J

  1.the balanced   chemical equation is as below

cu +   2 ag(no)₃ → cu(no₃)₂   +2 ag

2.the   much silver   produced   is   50.9 g

step 1: find the   moles of cu

moles =   mass÷   molar mass

  from periodic table the molar mass of cu = 63.5 g/mol

moles is therefore = 15.00 g÷ 63.5 g/mol = 0.236   moles

step 2: use the mole ratio to determine the   moles of ag

from equation above   cu: ag   is 1: 2

therefore the moles of ag   =0.236   moles   x 2/1 =0.472   moles

step 3: find the mass   of ag

mass = moles x molar mass

from periodic table   the molar mass of ag =107.87 g/mol

mass   = 0.472   moles x 107.87 g/mol = 50.9 g

3.   the   much   silver   collected worth is   1.797 oz

  convert   50.9 g   to oz

that is   1 gram = 0.0353 oz

          50.9 grams =?   oz

by cross multiplication

={(50.9 grams x 0.0353 oz) / 1   gram}   =1.797 oz