Recent content by dnl65078

Homework Statement a)A sound wave with an intensity level of 80.1 dB is incident on an eardrum of area 0.600 10-4 m2. Calculate the energy is absorbed by the eardrum in 4.00 minutes in microJ b)The sound level 25.0 m from a loudspeaker is 69.0 dB. Calculate the rate at which sound energy is...

Homework Statement Please help with this problem! How many sprints from rest to a speed of 4.5 m/s would a 59 kg woman have to complete in order to burn off 5.0 x 102 Calories? (Assume 100% efficiency in converting food energy to mechanical energy.) Homework Equations...

so do i just multply by 6.02e23?

Homework Statement A sample of an ideal gas is at a temperature of 320 K. The rms molecular speed at this temperature is measured as 1631 m/s. Calculate the mass of a molecule of this gas Homework Equations rms velocity , u = √(3RT/M ) The Attempt at a Solution Given u = 1631 m...

Homework Statement A sample of an ideal gas is both compressed and cooled. The given variables for the gas are: P1 = 90.0 kPa, V1 = 0.0800 m3, V2 = 0.0400 m3, T1 = 300. K, T2 = 260. K. Calculate the final pressure. Homework Equations PV=nRT P1 V1 /T1 = P2V2 / T2 The Attempt...

So i multiply that answer by 1x10^-6 and that should give me the right answer ?

I am using webassign so when I input the wrong answer it tells me so.

Do i have... 2.69x10^25 molecules?? Sorry I'm a total physics idiot.

Hey I'm right there with you. He doesn't do anything. but give me a sec.

the "u" is what's throwing me off. I've never seen that before

Do I have to convert u into kg??

Thats just the thing. I cannot figure out what formula to use. The formula's I have are PV=nRT and PV=NKbT... none of the formulas I was given seem to be valid for a "change in temp/volume"

Homework Statement At standard temperature and pressure (273 K and 1 atmosphere), oxygen has a mass density () of 1.43 kg/m3. The molecular mass (m) of oxygen is 32 u. Calculate the number (n) of molecules in one cm3 of oxygen. (Round to three significant figures.) Homework Equations...

Please Help! Kinetic Energy Problem 1. The initial pressure in an ideal gas is 1.40 atm when its temperature is 299 K. The temperature is increased to 315 K and the volume is increased to 1.29 times its initial value. Calculate the final pressure. 2. R = 8.31 J/molK PLEASE HELP...