Chris asks…
How do you solve motion in two directions problems in physics?
Having a little trouble with solving problems that have to do with projectiles in 2 directions. What should I look for in a problem to make it easier to solve? And how do I know that an answer is right?
Also, how should I organize my x and y values? Thanks alot.
Nagesh answers:
Projectile problems: You use the angle with horizontal to resolve the initial speed into x and y velocity components. Like vx = s cos(theta) and vy = s sin(theta) where s is the speed and theta the angle with horizontal. Then, you work the two directions sort of independently. In the x direction horizontal to the ground the projectile travels at constant speed so your equation is just dx = vx * t
In the y direction the projectile starts traveling up but slows from gravity pulling it back. The equation is dy = vy * t – (g/2)*t^2. Usually we do it this way so that dy = 0 at ground level. One thing to be careful about is putting all your known quantities into a consistent set of units like m/s, m/s^2, m and s. Then you put the known quantities into the equations and solve for the unknown.
If you have trouble getting started, you might try writing down the four equations I give here on your work sheet and then begin identifying which quantities you know and which you don’t.
Another thing to look out for is that physics problems often use realistic numbers where the answers must be done on a calculator and do not come out even numbers like you get used to in algebra classes. Messy looking decimal numbers are ok as answers, but you need to be careful about checking your answers because you can’t just look at it ans see it is ok.
Nancy asks…
What are some simple directions for a person traveling from Grandin mo to Marble Hill also in mo?
Ok, I need some easy directions for my bf so he can get from Grandin mo to Marble Hill mo. If you can, please give me directions, thanks.
Nagesh answers:
Just type that into google maps and you’ll get easy to follow directions.
Maria asks…
Is there a street where the toilet flushes in opposite directions on either side of the street?
If the toilet flushes in opposite directions depending on which hemisphere you are in, there should be a transition point somewhere. If there is, what happens to the water at that point?
Nagesh answers:
I imagine on the equator, the water can’t make up its mind as to what direction it wants to spin. Now that you mention it, I should have observed what it did when I went into the southern hemisphere.
Laura asks…
How can I send driving directions directly to my cell with googlemaps?
if i look up directions on my comp and want to send them to cell how can i do it?
my phone is samsung behold 2
it works thank you!!
now if only i can figure out how to give u best answer…
Nagesh answers:
You can save Google maps on your PC (they get saved in Google’s cloud, in you account, not on the local computer). After you create the map with the driving directions on the computer, save it to “My Maps.”
Now, open Maps on the Android phone. Press Layers, the press the More Layers button. Press My Maps. There you will see a lit of the maps you have saved in your Google account. Press the one you want and it will be synced to the phone.
Google also allows you to do turn-by-turn voice navigation with the Maps tool in Android. You may have to install it from the Market, depending on what version of Android you’re running on the device.
James asks…
How to parameterize a motor with a single VFD while the motor travels or rotates in 2 directions?
How to parameterize a motor with a single VFD while the motor travels or rotates in 2 directions (you may say reverse and forward directions) travels in 1 direction for some distance and then returns back to its mean position or starting position ?
Which parameters would be very important ?
Also how to hard wire it (how to hook up the setup) ?
The drive is 3.7KW YASKAWA H1000 drive or G7 Drive ….
The motor make to run the trolley to take the billet (or move with the billet) till the gas cutter fitted on the trolley completely cuts the billet in required size it can be 3m or 6m or 9m in length .
thanks
Nagesh answers:
Download the manual for the VFD. It should be easy to find the parameter that enables reverse operation. There may be another parameter to assign the directions commands to terminals. You may want to assign preset speeds to one or both directions. You may be able to assign the speed selection command to the same terminal as the direction command.
One way to control travel for a specific distance and stop at a defined positions is to install limit switches at the required positions. You may want additional switches at “slow-down” points. That may require sufficient logic and I/O to require a PLC. The VFD may have some built-in PLC functionality.
Another approach is to install an encoder that can determine the exact position of the cutter in the range of travel. The PLC would then be programmed to give the appropriate commands to the VFD based on position. There may also be some consideration of detecting the progression of the actual cut.
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