# Posts by samm

Total # Posts: 29

physics
a particle which has zero rest mass and non zero energy and momentum must travel with a speed?

physics
A convex lens with a focal length of 20 cm is placed in front of a convex mirror with a focal length of 7.5 cm. A luminous object is placed in front of the convex lens at a distance of 40 cm from it. What is the distance between the mirror and the lens to get the object's ...

physics
a small piece of wire bent into L shape with upright and horizontal positiions of equal lengths, is placed with horizontal position along axis of concave mirrror whose radius of curvature is 10cm. If bend is 20cm from pole of mirror, then ratio of lengths of images of upright ...

this is what i got: cost=6*2PIr^2+5*2PIr*h = 12PIr^2 + 10PIr*h = 12PIr^2 + 10PIr*(6/r^2) = 12PIr^2 + (60PI)/r

can you please explain how you got these equations?

joe is building a wooden cylindrical storage box. the box will have a volume og 6pi m^3. for design purposes, the thick wood for the top and the bottom costs \$6/m^2 and the thinner wood for the sides cost \$5/m^2. a)express the cost of the wood as a function of the radius. make...

chemistry
Consider 15 mL of an aqueous solution containing 2.0 g of an organic solute. If the distribution coefficient for the solute between ether and water is 20, calculate the percent of the compound that can be recovered with a single extraction with 13.9 mL of ether

chemistry
ok so you have 1.76g of salicyic acid(138.12 g/mol) and with 1.11 g of acetic anhydride(102.10 g/mol) a student obtained 1.12g of acetylsalicylic acid( 180.17 g/mol) what is the percentage yield?

chemistry
The half-equivalence point of a titration occurs half way to the end point, where half of the analyte has reacted to form its conjugate, and the other half still remains unreacted. If 0.220 moles of a monoprotic weak acid (Ka = 3.7 × 10-5) is titrated with NaOH, what is ...

chemistry
500.0 mL of 0.140 M NaOH is added to 625 mL of 0.200 M weak acid (Ka = 1.37 × 10-5). What is the pH of the resulting buffer?

physics
A firecracker in a coconut blows the coconut into three pieces. Two pieces of equal mass fly off south and west, perpendicular to each other, at 21m/s . The third piece has twice the mass as the other two. What is the speed of the third piece? What is the direction of the ...

Chemistry
A voltaic cell consists of a Pb/Pb2+ half-cell and a Cu/Cu2+ half-cell at 25 C. The initial concentrations of Pb+2 and Cu+2 are 0.0500 M and 1.50 M, respectively. A. What is the initial cell potential? B. What is the cell potential when the concentration of Cu+2 has fallen to ...

College Chemistry 104
A voltaic cell consists of a Pb/Pb2+ half-cell and a Cu/Cu2+ half-cell at 25 C. The initial concentrations of Pb+2 and Cu+2 are 0.0500 M and 1.50 M, respectively. A. What is the initial cell potential? B. What is the cell potential when the concentration of Cu+2 has fallen to ...

Physics HELP!
A 85.0 kg base runner begins his slide into second base when he is moving at a speed of 2.10 m/s. The coefficient of friction between his clothes and Earth is 0.570. He slides so that his speed is zero just as he reaches the base. (a) How much mechanical energy is lost due to ...

ETH125
Any time in american history? I know they immigrated but as far as i have read i do not think they suffered any of the three. Do you know any good websites i could look up with a lot of information on hungarian history.

ETH125
Did Hungarians face prejudice, segregation, racism, or any combination of the three?

ETH125
Did African Americans go through annexation?

English
thxs :D i hope i don't do it wrong by accient :o then my princble will probebly make me do my h.w. in her office for the rest uv the year again :o

English
yes that is the website

English
hi im sam :p i have 8th grade math and i think like yesterday we got an assesment called circle sentencing and im completly confused i even asked my princble and she couldn't even help..:( i have a link to show what my homework is but it wont let me post it but if you look...

chemistry
how much heat is released when 5.60 moles of NaOH is dissolved in water?

General Chemistry
Methanol is produced as the sole product of the combination of carbon monoxide gas and hydrogen gas. If 3.12X103 kg of methanol are actually produced, what is the precent yield if you start with 430.0 kg of hydrogen gas?

Digit Problems
If the tens digit of a two-digit number is subtracted from the units digit, the difference is 8. The number with the digits reversed is 10 more than nine times the units digit of the original number. Find the number.

Chem
Calculate the number of grams in each of the following. (3 s.f.) 19. 0.550 mol Au ________________________

college
18.0 grams of oxygen is reacted with nitrogen to make 56.0 grams of nitrogen dioxide according to the following reaction: 2O2 + N2 ---> 2 NO2 How much nitrogen (in grams) reacted?

chemistry
how many totsl moles of ions are released when 0.83 mol of K3PO4 dissolves in water?

geometry
ughh i need help i dnt like proofs we'll here it the instructions write a two column proof the segment addition postulate is useful for this proof also. remember that the transitive && substitution properties are common in proofs this one requires substitution.. given is ...