# Exercise 9: A little more physics

**(15 minutes)**

Assuming a relativistic particle, the measured energy of the particle in our example n-tuple is given by

\[E_{meas}^{2} = p_{x}^{2} + p_{y}^{2} + p_{z}^{2}\]

and the energy lost by the particle is given by

\[E_{loss} = E_{beam} - E_{meas}\]

Create a new analysis macro (or revise one of the ones you’ve got) to
make a scatterplot of \(E_{loss}\)
vs. ** zv**. Is there a relationship
between the z-distance traveled in the target and the amount of energy
lost?