Do x-ray have higher or lower energy than Uv Light ?

Explain..

An incident ray through the focal point of a spherical mirror will: reflect through the center of curvature. reflect back through the focal point. reflect parallel to the principle axis. reflect the same direction as the incident ray.

Four identical lab carts each have a mass of 200 kg. different masses are added to the carts and the velocities are measured. all carts move to the right.

How is the ideal mechanical advantage of a wheel and axle calculated?