1. C

    Ratio of N between two atoms

    lifetime of the 4p state of atom A is 21.4 ns and the lifetime of the 3s state of atom B is 14.4 ns. At t = 77.5 ns the rate at which a sample of atom A in the 4p state is decaying is 5.20% of the rate at which a sample of atom B in the 3s state is decaying. What's the ratio of the...
  2. B

    Finding correct gear ratio

    I'm trying to find a formula that will allow me to predict what rear end gear I would need to run at a particular oval race track. For instance, Say we run at Daytona, a 2.5 mile track, in a 3400lb car with 850 hp engine turning 8200rpms and tire circumference of 85in and a 1:1 final...
  3. G

    Stoichiometry Ratio and Tight-binding Model

    Is Stoichiometry ratio important in tight-binding approximation ? i am going to calculate energy band structure of Vanadium dioxide using this approximation, so i have to determine its unit cell first (the unit cell of VO2 is shown at Fig 1). (Figure 1. tetragonal unit cell of the high...
  4. A

    Ratio of isotopes in mixture

    A mixture of I(131) (half-life 8 days) and I(132) (half-life 2.3 hrs) has an activity of 5kBq. After 12 days the activity is 1kBq. What proportion of the 5kBq was due to I(132)? I(131) decay constant=ln2/(8*24*60*60)=1.00*10^(-6) I(132) decay constant= ln2/(2.3*60*60)= 8.37*10^(-5) N=...
  5. M

    ratio of translational kinetic energy to rotating kinetic energy

    An object is rotating without slipping. What percentage of its total kinetic energy is its translational kinetric energy if the object is a uniform sphere? So this would be \frac{K_{rotational}}{K_{trans}} so for a solid sphere the moment of inertia is .5MR^2\frac{2}{5}MR^2 so this gives me...
  6. A

    Ratio problem

    Air at 273K and 1.01*10^5 Nm^(-2) pressure contains 2.70*10^(25) molecules per cubic meter. How many molecules per cubic meter will there be at a place where the temperature is 223K and the pressure is 1.33*10^(-4) Nm^(-2)? I know this has got to do with ratios. I found n=(pV)/RT for both...
  7. C

    ratio of acceleration

    Hello everyone, Could you please verify that I did this correctly? If m1=2m2, and the same force F is applied on these two objects, what would the ratio of acceleration a1/a2 be? Me attempt: F=m1a=F=2m2a F=m2a 2(m2)a1=m2a2 a1/a2=m2/2m2 Thank you very much
  8. W

    Problem on ratio of mass of gas

    There are flasks X and Y which are connected by a thin tube. T. Volume of X is twice that of Y.Both flasks are filled with an ideal gas and a steady state is established with the flask X and Y held with the flasks X and Y held at 200K and 400K respectively. What is the ratio of the mass of gas...