# Search results

1. ### Mini-project help please

The physics involved in this experiment.. I've started with talking about gravity and air resistance. Is there anything else i can add to this?
2. ### Mini-project help please

Thanks for the suggestions. How can I explain the physics behind this?
3. ### Mini-project help please

thanks but is it just me or are the attachments not working?
4. ### Mini-project help please

Yeah i tried the paper helicopter thing but that only lasted me a little over 3 seconds
5. ### Mini-project help please

Our teacher supplied us with one 8.5x11 sheet of paper, 2 paper clips and 12in of masking tape. What we have to do is put this stuff together and release it from about 9 feet above the ground. I has to stay in the air for 8 seconds or more and land inside a box on the floor (which means it...
6. ### Precal - Rotation of a Conic

umm.. iono about that but I know that rsin(theta) is y and rcos(theta) is x.. would that be the same?
7. ### Precal - Rotation of a Conic

Ok. So i got that part where you replace x with x'cos(theta)+y'sin(theta) and y with -x'sin(theta)+y'cos(theta). My book shows us the proof for this using matrices. What my teacher wants us to do its prove this using polar equations or something like that. I started out with the drawing...
8. ### Help please, motion of charged particle in mag field

ok i got the correct answer now.. THanks a lot!! :D
9. ### Help please, motion of charged particle in mag field

hmm so r=mv/qB is derived from mv^2/r=qvB. I got r=(1.4x10^-8)v. the thing is.. i dont kno the relationship between the time, radius and velocity. Do i use r to find the circumference and multiply that by the velocity? im not really sure.. thanks for the response
10. ### Help please, motion of charged particle in mag field

A proton moves in a circular orbit perpendicular to a uniform magnetic field of 0.758T. Find the time it takes the proton to make one pass around the orbit. Just need someone to help me start off. All I have is that the B=0.758T, q=1.6x10^-19C and m=1.67x10^-27kg. What formulas do I need...
11. ### Electric field question

ok thanks a lot!! i reallly appreciate it :-D
12. ### Electric field question

hmm.. is it m=1.67x10^-27? what is q?
13. ### Electric field question

yeah i got that but its not given in the problem..
14. ### Electric field question

hmm im lookin for a right? so what am i suppose to plug in for m and q? im confused..
15. ### Electric field question

A proton accelerates from rest in a unifor electric field of 640 N/C. At some later time, its speed is 1.20X10^6m/s. Find the magnitude of the acceleration of the proton. Hmm.. not sure what formula to use on this one.. can someone help?
16. ### Help please thermal expansion

ok i got it now.. i did the area part wrong Thanks to both of you for the help :D
17. ### Help please thermal expansion

hmm.. after you got the change in length, what did you do after? Did you plug it into the Young's modulus formula? If so, what did you use as the area? I was confused about this part of the problem.. Thanks for the response :D
18. ### Help please thermal expansion

The band below is stainless steel (coefficient of linear expansion=17.3X10^-6 degrees C, youngs modulus=18X10^10 N/m^2). It is essentially circular with an intial mean radius of 5.0mm, a height of 4.0mm and a thickness of 0.50mm. If the band just fits snugly over the tooth when heated to a...
19. ### Need help w/ centripetal acceleration lab questions

Um.. i wasnt sure about how to do #1 and 2 so i asked. And for #3 i found the velocity by using 2pi*r/t and got 7.95m/s. Then i used centripetal acc.=v^2/r and got 29.4m/s^2. Wasnt sure what the second question is asking.
20. ### Need help w/ centripetal acceleration lab questions

These questions are from a lab we just did. 1. Why is an unbalanced force required to produce circular motion? 2. The ratio of squared velocity to radius is a constant. In other words, the centripetal acceleration did not change as the radius changed. Explain. 3. In an amusement park...
21. ### Conceptual question

this is what i was thinking... Fn sin(theta) = mv^2/r (mg/cos(theta))sin(theta) = mg tan(theta) = mv^2/r tan theta = v^2/(rg) does that look right?
22. ### Conceptual question

An engineer wishes to design a curved exit ramp for a toll road in such a way that a car will not have to rely on friction to round the curve without skidding. He does so by banking the road in such a way that the necessary force causing the centripetal acceleration will be supplied by the...
23. ### Finding angular acceleration for this prob

What is the formula? The ones I have all have "wi" in it and I'm not sure I calculated that correctly.
24. ### Finding angular acceleration for this prob

A rotating wheel requires 3.00s to rotate 37.0 revolutions. Its angular velocity at the end of the 3.00-s interval is 98.0rad/s. What is the constant angular acceleration of the wheel? What i did was i used average w=delta(theta)/delta time. Then i used average w=radical(w^2+wo^2) to find...
25. ### Average force problem

A 3.0kg steel ball strikes a massive wall at 10m/s at an angle of 60degrees with the plane of thge wall. It bounces off with the same speed and angle. If the ball is in contact with the wall for .20s, wut is the average force exerted on the ball by the wall? its is wut i got.. p=mv p=mv...
26. ### Need help with hw momentum and collisions

i hav no clue how to do this problem... How fast can you set the Earth moving? In particular, when you jump straight up as high as you can, you give the Earth a maximum recoil speed of what order of magnitude? Visualize the Earth as a perfectly solid object. In your solution state the...
27. ### Need help with work and energy

thanks leong, i think i got part a now does ne one kno how to do part b?
28. ### Need help with work and energy

k used KEf+PEf+PEsf=KEi+PEi+PEsi to find the constant k and i got 3920N/M. Does that look right to ne one? wuts static equilibrium? i dont think i learned that yet
29. ### Need help with work and energy

nvm i got the answer for the first one using a different formula.. can someone help me on the second one?
30. ### Need help with work and energy

Two blocks, A(50kg) and B(100kg) are connected to a string. The pulley is frictionless and of negligible mass. The coefficient of kinetic friction between block A and the incline is Mk =0.25. Determine the change in the kinetic energy of block A as it moves from C to D, a distance of 20m up...