# Search results

1. ### Help! Electricity and work

Two identical point charges of q = +1.25 x 10-8 C are separated by a distance of 1.10 m. What is the minimum amount of work required by an external force to move them closer together so that they are only 0.60 m apart? I have no idea how to do this. I tried using -q(Vb-Va), but that got me...
2. ### A few questions about water pressure, temp, and sound

Please! I truly need help before 10:00!
3. ### Application of Vectors: Work (calc 3)

Wow! Take it easy! I wasnt trying to make fun of you. Geez.. I literally have never seen a problem like that before. How can that be taken as an insult? anyway, there is one more thing to try. Are you sure your calculator is in degrees/radians mode? (for whatever the problem calls for)
4. ### Application of Vectors: Work (calc 3)

Eh? Thats odd. Ive never heard of a problem neglecting gravity before. also isnt (dot) multiplication. NOTE: to a helper who is reading this: I really need help with my topci before 2 hours, please! :confused:
5. ### Application of Vectors: Work (calc 3)

You forgot about Vectors. Force is a vector. It has X and Y components. Also remember about Mass x Gravity.
6. ### A few questions about water pressure, temp, and sound

OK. I have done most of them correctly on my own, I need 2 checked and help with one: Check: A sound source emits sounds of frequency 210 Hz that travel through still air at 340 m/s. The source moves away from the stationary listener at 80 m/s. Find the wavelength of the sound waves...
7. ### Need help with 2 problems

So, the equation: Nf*L/2*sin(90-theta)=Us*Nf*L*sin(theta) Will solve the problem? Making this L/2*cos(theta)=Us*L*sin(theta) then 1/2=Us*tan(theta) then 1/(2*Us)=tan(theta) and finally: arctan(1/(2*Us))=theta? Also, just to be sure, is the answer to: It takes a...
8. ### Need help with 2 problems

Wait.. is it just L?
9. ### Need help with 2 problems

1. OOPS! Im such an idiot. That was supposed to be the mass. If 460 is repalced with 520, will the problem be correct? 2. I thought I needed to meansure the length from where mg affects the ladder, in the middle. Also Im having trouble since the only value given is the coefficient of...
10. ### Need help with 2 problems

1.A 110 kg scaffold is 6.8 m long. It is hanging with two wires, one from each end. A 520 kg box sits 2 m from the left end. What is the tension in the left wire?(g = 9.8 m/s2) For this one I tried using: 6.8 *t=460*9.8*4.8+110*9.8*6.8/2 and solving for t, but I for some reaosn get...