(adsbygoogle = window.adsbygoogle || []).push({}); Statement of the problem :

"Using the definitionL=r##\times##p, prove that thedirectionofLis constant for an alpha (##\alpha##) particle whose scattering is shown in the diagram below. "

Relevant equations :

We are aware that the scattering takes place via a central forceF =F(r) ##\hat r##. Angular momentumL=r##\times##pand torque ##\tau = r \times F## (all vectors)

The attempt at a solution

I can solve the problem, but not the way it asks. The torque ##\tau = r \times F \Rightarrow \tau = 0## since the force is central :F= F(r) ##\hat r##. Using ##\tau = \frac{dL}{dt} = 0##, inplies that the angular momentum vectorLis constant.

[This is not what the question asks for. It asks to show only thedirectionofLconserved, from the definition ofL:L=r##\times##p].

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# Alpha Particle Scattering and angular momentum

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