Recent content by Banana

For part c, I always remember to have Fun. Frictional Force=coeff of friction*normal force. Rearrange and solve for u. (I know, it's not a u, it's a mu, but who wants to have fmun?)

To reinforce what Halls of Ivy told you, you always disregard any force that is 90 degrees away from the direction of displacement. If there were a force at 89 degrees, you would find the vector components and use that horizontal component, no matter how small. It's not because normal force...

BTW, the answer is 7, not 17/11. Unless we are misreading your original problem.

If your equation is as dexter thinks, then the first thing I would do is take the cube root of 27 and just change that part to a 3. Then, anytime you have a variable in an exponent, you just take the log or ln of each side. It turns it into an easy equation. For instance to solve 3^x = 12...

Now don't you think WQED is a little more interesting?

These are inelastic collisions, meaning after the 2 things hit, they stick together. So you can treat the 'after' part of the equation as one thing. That's what Cyclovenom is saying. The next step is to replace momentum with mass and velocity: m1 * v1 = (m1 + m2)v'. Note: v' stands for...

Speed of sound If you're not given an air temperature, you can just use 331 m/sec as the speed of sound.

I'd start with sketches dividing the trip up into accelerating, constant and deccelerating parts. My sketch would look kind of like a number line, and I'd write in what was given and what I could find out about each part.

I agree with Tide. You are supposed to ignore the Earth's motion, but not the fact that the world is round. It's like when a car goes around a race track even at a constant speed, its velocity is considered to be changing because its direction is changing. And the definition of acceleration...

I have a good tip for free-fall problems: After your diagram, you always write four things -- three givens and one with a question mark. Otherwise, you may think you don't have enough 'givens'. For example, if they ask the initial velocity it would take to reach a height of 10 meters, you...

Can someone double check me please? I'm not sure if it matters that the fourth and first orders are missing. Reduce to a first-order equation: 2y''''' + 12x^3y''' - 2y^7y'' - 8y = 0 My solution: u1' = u2 u2' = u3 u3' = u4 u4' = u5 u5' = -6x^3(u4) + y^7(u3) + 4(u1)

Always have FuN with friction. (F = u N). F will always be your horizontal force (or horizontal component if on a ramp), u is the coefficient of friction, and N is the normal force. This is an easy way to remember the formula and will help you remember not to try to use mass. Remember the...

They're equal. If you need any other angles, extend the rays on your sketch and use geometry to find what you need. Remember, if they give you the angle relative to the surface to use its complement as the angle of incidence.

Sounds like you're talking about dispersion; like in a prism. The index of refraction differs slightly for different wavelengths (colors). (The index of refraction is how quickly light travels thru the medium as compared to air). So if blue light has a wavelength of 400 nm and an index of...

Sorry; I meant divide each side by v