1.  Space-time is a combination of space and time.
    How do we combine them into a single set of units?

      a) use frequency as a conversion factor

      b) use mass as a conversion factor

      c) use the speed of light as a conversion factor


2.  Mom-energy is a combination of momentum and energy.
    How do we combine them into a single set of units?

      a) use frequency as a conversion factor

      b) use mass as a conversion factor

      c) use the speed of light as a conversion factor

3.  Fred holds a ball motionless in his hand.  He
    measures the mom-energy of the ball, which is equal to

      a) the ball's momentum

      b) the ball's kinetic energy

      c) the ball's rest energy