friction and inertia

1. Does friction torque in speeding up = speeding down?

On speeding up: τload - τfriction = Iαup On speeding down: τfriction = Iαdown If i substitute τfriction from speeding down to speeding up equation, i get moment of inertia: I = (τload)/(αup+αdown) But, is this allowed? Does friction torque in speeding up is equal to friction torque in...
2. Rotating with slipping to rotating without slipping?

It seems to me that this transition implies going from kinetic friction to static friction. The kinetic friction would apply a torque that would slow down the object's angular velocity, but I'm not sure how this connects to the object suddenly transitioning into rotating without slipping.
3. Object causing another object to move with zero friction

1. Homework Statement This is the problem from the book "physics for scientists and engineers..." by Serway, Jewett / Chapter 5, problem 98 Initially, the system of objects shown in Figure P5.93 - is held motionless. The pulley and all surfaces and wheels are frictionless. Let the force F be...
4. I Trying to better understand what viscosity really is

I'm trying to get a better handle on the actual physical phenomena underlying viscosity (for newtonian fluids). Something I could word in the format of "this happens (and this and this), and so the fluid resists flow." What I've found online is that when gasses are at higher temperatures, they...
5. How could the block A move to the left corner?

1. Homework Statement See question number 5. 2. Homework Equations F=m*a W=F*s Uniform acceleration motion equations 3. The Attempt at a Solution Actually,I am having some difficult understanding the problem. See the F.B.D of the system, see the friction is acting on the block in the...
6. I Can a bicycle be tipped over by only applying rear brake?

Let's say I'm riding a bike at constant speed. Also assume that the person riding is rigid, no moving of the persons body, constant center of gravity. Assuming that there is sufficient friction between the tires and road. If I apply the front brakes, I will likely tip over. If I apply the...
7. Negative Values of the Frictional Force?

1. Homework Statement Ignore B & C for now The block in the figure reaches a velocity of 40 m/sec in 100 m, starting from rest. Compute the coefficient of kinetic friction between the block and the ground. W = 100N F = 40 N 2. Homework Equations ∑Fy = 0 so Normal Force = Weight ∑Fx =...
8. Projected Block and Conveyor Belt

1. Homework Statement It is a Matching Type Problem(a single entry in a column can be matched with more than one in the other column):- A block is projected with an initial velocity $v_{\text{Block}}$ on a long conveyor belt moving with velocity $v_{\text{Belt}}$(at that instant) having...