Recent content by hsbhsb

  1. H

    2D elastic collision in CM Frame, velocities antiparallel?

    Homework Statement Why are the Center of Momentum velocities of masses after a 2D elastic collision anti-parallel? (as in the following diagram) Homework Equations CM_Velocity = (∑m_i*v_i)/(∑m_i) The Attempt at a Solution This is not actually a problem I have to do. I am just looking for a...
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    Understanding derivation of -du/dx = F

    Yes it is meant to, my mistake for lack of clarity. From now on I will use ##dU## instead of ##du## to represent the derivative of ##U## Does it ##=F+dU/dx##? Ok, I can see why ##ΔU \neq dU## in this case. After all, ##ΔU## represents a real change in potential, not an infinitesimally small...
  3. H

    Understanding derivation of -du/dx = F

    Homework Statement Where U is potential energy, show that F = -du/dx Homework Equations ΔU = U(x) - U(x_0) $$ΔU = U(x) - U(x_0) = \int_{x_0}^{x}Fdx \qquad (1)$$ The Attempt at a Solution [/B] I am confused why $$\frac{d}{dx}ΔU = \frac{du}{dx} \qquad (2)$$...
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    F = ma equations for circular movement (roller coaster)

    Homework Statement Come up with expressions for centripetal acceleration at the top of the small hump and the bottom of the loop. (this is one substep in a larger problem) Homework Equations f = ma The Attempt at a Solution Taking down to be negative, I believe that the f = ma equation at...
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    Arclength Problem; stuck on integration

    Homework Statement Find the arclength of $$r(t) = <{t}^2/2,{t}^3/3>$$ from t=-1 to t=1 Homework Equations I have used this equation for arclength $$\int_{-1}^{1}|{r}'(t)|dt$$ The Attempt at a Solution After integrating (using u substitution) I have the solution...
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