Recent content by minimario

Homework Statement So during collisions between 2 point masses, I know that momentum is always conserved, but energy may or may not be conserved. Now, in this case, where we have a block colliding with a pivoted rod, I know that angular momentum is always conserved, but neither energy or...

Then, why, when integrating the sphere, it is ok to ignore the curved area? And the 1/2, it is right because we are summing the moments of each individual disk, which is 1/2 MR^2

Homework Statement Find the moment of inertia of a spherical shell (hollow) with mass M and radius R. Homework Equations ## I = \int r^2 dm ## The Attempt at a Solution This is method I use to find Moment of Inertia of solid sphere: We use circular cross sections. At some radius r...

Exactly :)

If I go 1 mile at 10 miles/hr and then go 1000 miles at 1 mile/hr, the average velocity would obviously be very close to 1, where the majority of your time is spent. Using your method, it would be (11+1)/2 = 5.5, clearly wrong. Taking the average only works when the times taken are the same...

Oh. So the friction on the top book would be right, and that on the bottom book would be left.

To the right, but when I put a book on top of a heavier book and pull the heavier book right, the book goes left and falls off?

Accelerate left. So the friction force would be left?

Homework Statement Homework Equations F = ma The Attempt at a Solution When drawing a FBD for block 1, I couldn't figure out if the friction force between the blocks was toward the left or toward the right. Similar situation on block 2. How would I determine this?

Homework Statement Homework Equations ##v = r \omega ##?? The Attempt at a Solution The answer is 0...why?

Here's another problem on the same topic, that I can't decide

Thanks, got it now!

Homework Statement 2. Homework Equations Elastic collision: KE conserved The Attempt at a Solution I don't think there's really anything to work out...why would the 2M block move right as well?

Edit: never mind, delete the thread. (I cannot find delete button) Edit 2: Replaced with new problem, that I do need help with.

Homework Statement Homework Equations W = Torque * distance 3. The Attempt at a Solution The net torque is 8*.09-11*.06 = .06, and the distance moved is 4pi, because 2 full rotations, but this is not one of the choices...