# 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

:::{math}
E_{meas}^{2} = p_{x}^{2} + p_{y}^{2} + p_{z}^{2}
:::

and the energy lost by the particle is given by

:::{math}
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?