Recent content by eterna

So is the correct integral from 0 to L(length of the plate) : μ u'(0) width dl ?And so for the total force( top + bottom of plate), is it just two times that?

Homework Statement http://scienceofdoom.files.wordpress.com/2010/12/convection-basics-1b.png How do I find the total force on that surface of the plate? Homework Equations T = μ * u'(y) where T is the shear stress, μ is a scalar constant - the viscosity and u'(y) is the velocity gradient...

http://postimg.org/image/onxjqc26l/ I have found the shear stress of the inner cylinder to be 405 Pa like in the solution but I am having trouble visualizing the total moment of this stress about the center line. I was wondering if someone could explain where that d(theta) in the moment...

so is the sd = (70-38)/6 ?

Homework Statement Suppose that an investigator believes that virtually all values in the population are between 38 and 70. The appropriate sample size for estimating the true population mean within 2 units with 95% confidence level is approximately how much? Homework EquationsVariance of the...

Homework Statement "Assume you want the car to accelerate towards the right. When a wheel is spinning, the contact point with the ground is moving towards the left. The direction of the frictional force on the portion of the wheel contacting the ground is opposite to the direction of the...

thanks and by "find the friction required so that the wheels of the car do not slip", what exactly do they want once I've found the friction from doing the problem?

Homework Statement http://postimg.org/image/vnn9m9au9/ For the car why is the friction acting towards the left. Shouldn't it be towards the right since the car is moving to the left And why is there no friction for the trailer? Homework Equations The Attempt at a Solution

Homework Statement http://postimg.org/image/mzdo4kp7b/ wouldn't the initial angular speed of 50rad/s cause some rotation about the axis at B (so shouldn't the FBD include a torque about B?) http://postimg.org/image/nad9b9rqn/ And in this question, I don't know what Mz is. Is it...

so was what I said a completely wrong way of thinking about it?

Homework Statement What does it mean? Is this the interval such that 95% of the means from a sample mean distribution (frequency distribution of means of sample size n) are a certain number of standard deviations from the population mean? Homework Equations The Attempt at a Solution

The book says that a sinusoidal voltage v(t)=Vcos(wt+ ##\theta##) can be defined by the phasor V=V##\angle \theta## where ##\theta## is the phase angle The actual relation is V=##wLI\angle \theta## and that it can be written in the form V=##(wL\angle\theta)## x ##I\angle(\theta-90)## so...

Homework Statement Can someone explain how wLT /_ theta could be written as wL /_ theta X T /_ (theta - 90) (w, L and T are all constants)Homework Equations The Attempt at a Solution

so that means the probability of getting a specific number of successes is almost zero since there are an infinite amount of trials?

Homework Statement From a site introducing the Poisson Distribution "When trials can occur in a fixed continuum of time (or distance), each instant of time (or distance) is essentially a distinct trial. Because a continuum contains an infinity of points, this means a statistical...