Recent content by Impulse

Is the most robust definition of work: Wnet = ΔEsystem ? Also, under what conditions does Wnet = ΔKE not apply? Later in the chapter the text makes a distinction between "conservative" and "nonconservative" forces and defines: Wnet = Wc + Wnc = -ΔU + Wnc Therefore by substituting Wnet for...

The way I interpret the question, force P is not friction but an external force such as a push that points to the right (in the direction of point B) and acts on the object in addition to friction (which points to the left in the direction of A opposite the object's motion.) Force P causes the...

Wnet = ΔKE By this equation, if I lift a 1 kilogram book at rest from the ground and place it to be at rest on a table 10 meters above the ground, no net work has been done on the book. (Its kinetic energy before and after is zero.) However, its potential energy has changed by mgh or 1kg *...

. (I accidentally replied when I meant to edit my original post.)

The formula you'd like is: Worknet = ΔKE We can let the work done by force P be positive, and we can let the work done by friction be negative. Substitute in the sum of the work done by those two agents for work net in the above equation to solve for work done by friction. @BvU: Force P acts...

Homework Statement The problem motivating this post is: "An out-of-gas car is rolling over the top of a hill at speed v. At this instant, a. n > FG b. n < FG c. n = FG d. We can't tell about n without knowing v." (Associated figure attached.) Homework Equations [/B] Newton's second law The...

Was very excited when I figured this out! Was this the direction in which you intended to point me?

Thank you guys very much for helping me head in the right direction on this. I'll keep looking into this on my own and wrestle with it some more and get back to you!

I think the basis of my understanding of velocity and acceleration is false. I thought that the acceleration vector was defined as the final velocity vector minus the initial velocity vector. My textbook has diagrams like this one that label the change in velocity vector as the acceleration...

Because by that logic we could multiply the acceleration by an arbitrary number of seconds, resolve it to the same unit as velocity, and then get an infinitely many different number of final velocities. With the \vec{v_f}=\vec{v_i}+\vec{a}t definition of final velocity, it seems to me like...

Our book actually discusses non-uniform circular motion too, and resolves the acceleration into a radial and tangential acceleration. So in uniform circular motion, there is no tangential component to the acceleration, and therefore the speed is not affected. What I don't understand is how...

Currently we're discussing uniform circular motion in my physics class. The previous unit discussed vectors and vector addition in the i, j, k format. When I try to apply the rules for vector addition to find the resultant velocity in uniform circular motion, I get an increase in the...

Is not the definition of acceleration the rate of change of velocity over time? Is it possible to have instantaneous acceleration? A classic definition of \overline{a} = (v_f - v_i) / t would be undefined at t = 0.

Standing wave diagrams are a still frame of where the wave will have traveled over time as it travels to one end of a medium and back. This is just like the graph of a wave on a coordinate plane. Some parts of the wave are crests, some are troughs, but they don't interfere because the crests...

Ahh, cool! My physics class (HS intro level) analyzed heat interaction as if specific heat was constant for all substances in all states at all temperatures. That intuitively sounds wrong. What determines specific heat at the atomic level? Is it very complex?