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Don't you have a TI-83 Plus graphic calculator? It can help you out a lot to confirm your answers.

As an undergrad engineer, I was taught to learn the SI metric system, and the U.S. metric system. If a question have metric units, then you should have the answer with metric units. Goes same for the U.S. metric system. But I did convert CanadaAots's answer, and it's right. I'll post my process of calculation tomorrow or Sunday. The maximum deleceration of the car is [math]29.0[/math] [math]ft/s^2[/math], or [math]8.84[/math] [math]m/s^2[/math]. I'll have another new problem post on Monday. Have a good weekend. P.S. I don't know how to delete post #5, sorry.

As an undergrad engineer, I was taught to learn the SI metric system, and the U.S. metric system. If a question have metric units, then you should have the answer with metric units. Goes same for the U.S. metric system. But I did convert CanadaAots's answer, and it's right. The maximum deleceration of the car is [math]29.0[/math] [math]ft/s^2[/math], or [math]8.84[/math] [math]m/s^2[/math]. I'll have another new problem post on Monday. Have a good weekend.

Please remain the answer in the units of feet per second squared.

I have recieved some private messages from SFN members asking me about posting up some physics questions. Apparently my "Speed of Sound" thread went dry, so I'll try this one more time, and hopefully, people will participate. The first question is a high schooler question, but it will challenge high school students, and people without formal education alike. If you can answer the question, good job. I'll put up another question as it will get harder as it goes on. 1st question: A family has purchased a new 45-inch television and because they only own a subcompact car, they have placed it on the roof, as shown. Because they had no rope, the father used double-sided tape between the box and roof to help hold the box in place (this isn't an overly bright family). The TV box weighs 90 pounds, and the coefficient of static friction ([math]\mu_s[/math]) supplied by the tape is 0.9. What is the car's maximum deceleration for which the box remains in a no-slip condition? Assume a flat roof that fully supports the box. Good luck.

People with no patience have a big issue. This weekend, Futureshop here in my area is selling PS3 for 1/2 the price. There'll be a lot of people waiting in the line. I never have the time to play video consoles because I'm too busy with university. But one of my friend is going to buy Nintendo Wii, and I can't wait for that. I'm particularly excitied about the new game - Zelda: The Twilight Princess.

Because gravity behaves as centripetal acceleration toward the center of the Earth. Simple.

Because you are day dreaming.

You flipped the coin for a reason - because you were bored.

Good point. Seems like my silly theorem is hard to prove it wrong, eh?

Maybe it's a defence mechanism for cyanide. I'm not sure about the seeds, but I'm sure there's a reason why it's big.

I'm no fan of subs. Sorry pals. I eat strawberry sandwiches every day for lunch though.

Yesterday, I had this crazy idea in my head from no where. My thoughts stated that everything is done for or within a reason. For example: We have to go to the bathroom to dispose our wastes We have bookbags to carry our materials We walk to go from point A to B I sat down to watch TV, or play computer These are some of the examples, and I want you guys to try to prove my silly theorem wrong. An example that something is not done for or within a reason. Good luck.

I have heard of him. He's an advanced physicst who sits in a wheelchair. I read an article on one of his lectures, and he appears to be really smart.

You should get a chalkboard. It'll help you in your future.

hotcommodity, if you have any further questions about linear algebra, please don't hesitate.

I'm currently taking Linear Algebra in University, and you won't need to panic on the first day. They will introduce you to the concept of a "vector". Then you will go on to vector addition, scalar multiplication, vector subraction. I recommend the "Linear Algebra: A modern introduction, 2nd edition by David Poole", if you want to get familiar with the materials. To let you know, the class is not really that hard, so you should be fine.

Anybody?

insane_alien is right. Electrons do not go in perfect orbit circles. It's just an idea how electrons actually works.

Gravity is also a long-range force.

Here is another physics problem. It's more challenge, and it's one of the questions from my university physics class. (Don't worry, I already passed my assignment in today). I have the answer for this question, so you can try the question yourself. If nobody can answer the question, then I'll give you hints. PROBLEM: Consider the illustrated system. A constant force of 10N acts in the x direction on block B. What are the accelerations of blocks A and B? [math]m_A = 10 kg[/math], and [math]m_B = 15 kg[/math]. Assume a frictionless interface between the two blocks and the ground. (All the pulleys are actually the same size, my drawing just sucks).

Also, I stated in the question, that the rock hit the water, meaning the water surface, that's it. You have to read the question carefully. My answer is right, I'm pretty sure.

Yeah, it was in my notebook, and I got confused when I saw the mxn. I was wondering how identity matrix could be mxn. Maybe it was a proof that my professor was doing. Anyways.

Ok, I'll give you an example. Let [math]A=\begin{bmatrix}1&2\\3&4\end{bmatrix}[/math], where [math]A=\begin{bmatrix}a&b\\c&d\end{bmatrix}[/math]. So you have a=1, b=2, c=3, and d=4. Using [math] A^{-1}=\frac{1}{ad-bc}\begin{bmatrix}d&-b\\-c&a\end{bmatrix} [/math], you replace the numbers. It would be: [math]\frac{1}{-2}\begin{bmatrix}4&-2\\-3&1\end{bmatrix}[/math] Since the denominator of -2 is not equal to 0, you know it's an inverse matrix. You then multiple it to the matrix. The inverse matrix would be: [math]\begin{bmatrix}-2&1\\\frac{3}{2}&\frac{-1}{2}\end{bmatrix}[/math] That's it for 2x2 matrices. To find the inverse for 3x3 matrices, it's farther more complicated. But it's almost similiar to the method above. OR, you can use Gaussian-Jordan Elimination, using the augmented matrix [math][A|I][/math].

Does anybody have any comments on my post #11?