Programming, .NET, Silverlight & More

I have started using WPF about two weeks ago… I have used WinForms for about 5 months. When I open Visual Studio (2010 Premium) I notice that the toolbox has less items [in WPF] than with WinForms. I have been searching for the timer control but haven’t found it yet.

Where is the Timer in WPF?
and
Why is the WPF toolbox ‘less full’ than in WinForms?

WPF has no timer control. That said you have far more options of every kind in WPF that you did in WinForms.

The object you need to find is DispatchTimer. You simply create an instance near the code where you use it and assign you handler code to its Tick event. That might be:

timer.Tick += MyHandler;

or even simpler

timer.Tick += (s, e) => { /* My code goes here */ };

I know the formula of net productivity, and I know primary production is the production carried out by autotrophs, but I can’t find the information for the average net primary productivity of a pond.

What kind of work are you doing??? sounds tough, go you! anyway thanks for answering my question

Mass of the crate is 50kg and the sliding friction is 100 N

What is the (a) net force and (b) the friction?

How did you do it?

You only can find the coefficient of friction
μ = F/mg = 100/(50×9.8) = 0.20

Net force can be found if net acceleration is known, and viceversa, by equation
F = ma
but if neither is known calculation is impossible.

Consider two point charges located on the x axis: one charge, q1= -17.0 , is located at x1= -1.685 ; the second charge, x2= 34.5 , is at the origin (x=0.000). What is the net force exerted by these two charges on a third charge q3= 52.0 placed between q1 and q2 at x3 = -1.245 ?

You didn’t include the units so I’m assuming distances are in meters and charges are μC

Now q1 and q2 both create a force to the left on q3

So F = k*q1*q3/r13^2 + k*q2*q3/r23^2

= 9.0×10^9*(17×10^-6*52×10^-6/(1.685 - 1.245)^2 + 34.5×10^-6*52×10^-6/1.245^2) = 51.5N to the left

I’m writing a small application in WPF/VB NET that looks like a regular form with several textboxes. Since it’s intended for use with touch screen, a kind of virtual keyboard should be implemented and put on the same form as the form text fields are.

What would be the best way to simulate keyboard input

it’s depend from your goals and project dead line. in case if you have a lot of time you can do it itself but in my opinion better way is to buy source code or similar project and integrate him in to your project.
in this way I would recommend you to visit http://fpscomponents.com/Products/WPF/vi… they have Virtual keyboard probably the same what you are looking for.

I know that when the net force and displacement are in opposite directions (such as only a frictional force on a moving object) the work is negative. However, if net force is positive, can an opposing force still do negative work? As an example, if I lift a box from the ground, I do positive work. But does gravity still do negative work, even though I am resisting that force and net force is positive?

Work is measured as the force multiplied by the displacement in the direction of the force.

Whenever there is a net force, the object will move only in the direction of the net force.
When the net force is zero, the object will be either in rest or in uniform velocity.
Work is measured by the product of the force and displacement in the direction of the force.
Positive and negative work
When object A transfers energy to object B, we say that A does positive work on B. B is said to do negative work on A. This use of the plus and minus signs relates in a logical and consistent way to their use in indicating the directions of force and motion in one dimension

Suppose that a ball is moving with some velocity from right side to left side on a horizontal table. The ball possesses some kinetic energy (1/2 mv^2)
It strikes a spring on the table and compresses it to some distance.

The ball does positive work on the spring. It imparts some energy to the spring.
The force exerted by the ball on the spring and the displacement are in the direction of the force.
On the other hand, the spring also exerts a force on the ball (resistive force).
But the displacement of the spring is opposite to the direction of the force of the spring on the ball. The spring does negative work on the ball. The ball’s energy decreases.

When the balls’ energy is completely lost, it comes to rest. But now the spring begins to elongate and still continues to exert a force on the ball and ball begins to go to the right.
Now the motion is in the direction of the spring’s force.
The spring does positive work on the ball. (The one which does positive work will loose its energy)
The ball also resists the elongation of the spring. It exerts a force on the spring. But the motion is in the opposite direction of this force. The ball does negative work. (The one which does negative work will gain energy). The ball’s kinetic energy now increases.

When you lift an object, you are doing positive work. The force is moved in the direction of the motion of the object. This means you are loosing energy.
The gravitational force opposes this action. It is pulling the object down ward, but the motion is upward. The gravitational force does negative work on the object. The earth gains energy. (Note that the potential energy of the object increases)

When an object is pulled along a horizontal road, the force pulling the object in its direction is doing positive work. It looses its energy. But frictional force acts in the opposite direction of the motion. Frictional force does negative work. The friction causing objects gain energy.
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I want to know what computer programming languages are needed to run a computer. More specifically how each hardware component operates the instance the computer is turned. This is in relation to the pieces of hardware running the computer like sound cards, hard drive, and how they operate from the ground up.

Also, any references to learning these languages would also be beneficial.

Hi,
http://www.learn-programming.za.net/ will suit you.

I use adobe dreamweaver for doing websites but there is one page on my site that does not synchronize correctly. It will keep going to the old linked page. I have tried putting entire set & that page alone. Also have cleared cache & browsing history. Despite the fact that it works fine in Dreamweaver it will not work online. Any thoughts. Thanks!

On the web host, is the file set to read only?
~
Have you tried deleting the file off the site before uploading the new page?

Is this thing supposed to be for my benefit? everything I read says other people are going to ask permission to store crap on my computer. Say what? I don’t think so! Nobody is going to use my computer for space. No way! No how! So can I delete it? What good is it? Why would MS even advertise such a thing?

Silverlight is like Adobe Flash. As far as other people storing stuff on your computer, I think you misunderstand. When you go to a web site that uses Silverlight, it’s going to store YOUR settings on your computer for Silverlight to function. Here are a couple of examples of what Silverlight does:

1. Netflix uses Silverlight to stream movies to your computer. When you’re watching movies on Netflix, that’s happening via Silverlight.

2. My local Sheriff’s department has a "Miranda’s Law" web page that shows where sex offenders live in my community. Silverlight is the technology that shows the map, lets me zoom in and out, and click on the red dots that represent sex offenders to find out exactly what they did to become a sex offender.

Someone asked me, how mathematics is important and have a vital role in computer science or programming. So I told her but I could not satisfy him. Please tell me in detail. Where and how in computer programming math is used very extensively .

Math is the basis and foundation of all computer science. A computer is something that calculates. Nothing more. And since calculations are the concepts of all mathematics, that is how they relate.

A computer only understands one language, which is "machine language" and when broken down is really just mathematics. When you type or do anything on a computer, the CPU translates all of the keystrokes into binary ASCII code, such as 1001 0010

When you move your mouse, the CPU translates the location of the mouse pointer as coordinates on the screen, such as X:106 Y:-568

I can’t answer for programming, but you can imagine the answers would be similar. Programs are simply a middle point for people and computers to understand each other. If the computer only speaks English, and the user only speaks Spanish, then "programming" is the translator in the middle so that each one know what the other wants.