My Nidoqueen has Sheer Force and a Life Orb, and all of its moves have 90 Power. How much power will they have after the applying of the Life Orb and Sheer Force (Not counting Special Attack and S.T.A.B.)( All moves have added effects (Ice Beam, Sludge Bomb, Earth Power, and Thunder Bolt))?
Life Orb increases base power by 30%, while Sheer Force increases base power by a conditional 30%. If a move doesn't have a secondary effect (like a burn chance), its base power will not be increased by Sheer Force, although Life Orb's bonus still applies.
The damage formula is a bit annoying to recall, but I believe that Sheer Force is applied to the base power of the move, which is then used to calculate the actual base damage during which Life Orb is taken into account. If I recall my multiplication properties correctly, this means that the increase in damage should be about
1.3 * 1.3 = 1.69 or a ~70% increase in damage.
Well, According to smogon damage calculation formula, documented here http://www.smogon.com/bw/articles/bw_complete_damage_formula
The basic steps of calculating damage done is performed using these steps in the exact order described. Here is the excerpt directly copy pasted:
Once the main parameters are set, the general steps of the calculation are as follows: BaseDamage = ((((2 × Level) ÷ 5 + 2) * BasePower * [Sp]Atk) ÷ [Sp]Def) ÷ 50 + 2 1.Apply the multi-target modifier 2.Apply the weather modifier 3.In case of a critical hit, double the value 4.Alter with a random factor 5.Apply STAB modifier 6.Alter with type effectiveness 7.Alter with user's burn 8.Make sure damage is at least 1 9.Apply the final modifier
In your particular case, Sheer Force affects the Base Power modifier, which is calculated before the BaseDamage formula is applied. Because all Base-Power, [Sp]Atk, [Sp]Def modifiers are calculated with modifiers before this formula.
LifeOrb comes under the final Modifier section of triggers which is much later on in the damage calculation pipeline.
The list of modifiers and which part they affect are listed in the link above. It is slightly puzzling to figure it out, but it is well worth the read to understand damage calculation in Pokemon.
So Base Damage is calculated with
1.3 * Base Power for Sheer Power and the Modified Base Damage is then calculated using
Base Damage * 1.3 for Life Orb.
PS: This is for Black/White and I don't expect it to have changed for X/Y by much since battling mechanics do not drastically change that much in Pokemon games.