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## Homework Statement

An alpha particle (a helium nucleus, containing 2 protons and 2 neutrons) starts out with kinetic energy of 10 MeV (10*10^6 eV), and heads in the +x direction straight toward a gold nucleus (containing 79 protons and 118 neutrons). The particles are initially far apart, and the gold nucleus is initially at rest. Answer the following questions about the collision.

What is the initial momentum of the alpha particle? (You may assume its speed is small compared to the speed of light).

## Homework Equations

1 ev=1.69e-19 J= 1.69e-19 kg*m

^{2}/s

_{2}

K=.5*m*v

^{2}

p=m*v

m

_{proton}=m

_{neutron}=1.7e-27 kg

## The Attempt at a Solution

I solved for velocity of the particle then multiplied it by its mass to find momentum.

10*1.69e-19=.5*m*v

^{2}

3.38e-18=8.8e-27*v

^{2}

497058823.5=v

^{2}

22294.81607=v

P=mv

P=8.8e-27*22294.81607

P=1.96194e-22