# Recent content by rowkem

1. ### Finding Ek with force, mass, and time.

Homework Statement A 10kg box at rest is being pushed on a frictionless surface by a force of 10N. The force is in the same direction as the motion of the box. 10 seconds later, how much kinetic energy will this box have? Homework Equations 1. F=ma 2. Vf=Vi+at 3. Ek=0.5mv2 The Attempt at a...
2. ### Figuring out the amount of CO2 that goes into the atmosphere when cooking a roast

I've changed the numbers a bit so things work out a little easier Homework Statement The combustion of propane in a BBQ follows the balanced chemical reaction: C3H8 + 5 O2 ---> 3 CO2 + 4 H2O As this reaction occurs, approximatley 3000J of heat is released. If a roast takes approx...
3. ### Faradays Law - Induced Current

Homework Statement A loop of wire is situation between a wire (Wire 1) that is perpendicular to the loop and another wire (Wire 2) that is parallel to the loop (the diagram has the loop and Wire 2 in the plane of the page, Wire 1 is running "through" the page). Is a current induced, and in...

So: we did an experiment to see if sow bugs liked a dry or a moist environment. We put them in a choice chamber and let them choose between a dry environment and a humid environment. We also did a seperate control where we gave them the choice between two identical dry environments. My...
5. ### Archived Charge and Energy for Capacitors in Different Configurations

Homework Statement How much energy must a 12V battery expend to fully charge a 0.15 uF and a 0.20 uF capacitor when they are (a) in parallel and (b) in series? How much charge flowed through the battery in each case? Homework Equations i: C(eq)=((1/C1)+(1/C2)+...+(1/Cn))^-1 and...
6. ### Why would leaves in a K+ solution have more open stoma than leaves in a Na+ solution?

OK - that has help immensely. I realize now that sodium channels are highly selective and I did a quick read up on the topic. Thanks. So - last question. Have plants evolved to have more potassium ion channels than sodium channels? If this is the case, then we can make some conclusions.
7. ### Why would leaves in a K+ solution have more open stoma than leaves in a Na+ solution?

Yes, I realize there is much literature on what potassium does, seeing as how that's what typically moves through the transport protein. There isn't lit though, on why sodium is less effective is opening stomata. Could it be that plants have simply evolved to use potassium, and therefore...
8. ### Why would leaves in a K+ solution have more open stoma than leaves in a Na+ solution?

Homework Statement So we did an experiment where we put a leaf section in KCl and another leaf section in NaCl. There was a marked difference in the percent of stomata that opening between the two. We let the two sections sit in solution for 60 mins each. The leaves in KCl had almost...
9. ### Speed of an electron in an electric field - want to check answer before submitting.

Took a stab at it. Was correct. Thanks everyone.
10. ### Speed of an electron in an electric field - trying to find my error.

That would do it. I end up getting 7.53x10^6 m/s. Seems high - thoughts before I submit?
11. ### Speed of an electron in an electric field - want to check answer before submitting.

Homework Statement Two stationary positive point charges, charge 1 of magnitude 3.45 nC and charge 2 of magnitude 1.85 nC, are separated by a distance of 50.0 cm. An electron is released from rest at the point midway between the two charges, and it moves along the line connecting the two...
12. ### Electric field

So.. F=Eq E=F/q - we know q but we need F. For it to hang suspended, there needs to be no net force acting on the bead. The electrostatic force is one of two forces acting on the bead; as well as being the F in our equation. So...this "other force" needs to be equal to the...
13. ### Speed of an electron in an electric field - trying to find my error.

Homework Statement Two stationary positive point charges, charge 1 of magnitude 3.45 nC and charge 2 of magnitude 1.85 nC, are separated by a distance of 50.0 cm. An electron is released from rest at the point midway between the two charges, and it moves along the line connecting the two...
14. ### Stoichiometry Help?

I know this is probably useless but, I thought I would give it some closure since some replies were filled with snide remarks and little was done to resolve the question at hand. First, I see nothing wrong with the equation, as far as I know, that's the combustion of sucrose and it's balanced...
15. ### How much energy does it take to cool and heat up water

As Borek said - water has to gain or lose energy to heat and cool, respectively. The enthalpy change is always in relation to the system. Heating: system gains energy: enthalpy change is positive Cooling: system loses energy: enthalpy change is negative Yes, that is correct. Cooling an...