Because mass is not always the same for objects made from the same material. Just because an object has the same mass as another doesn’t mean they are the same material.
Mass is the amount of matter an object has. We often use a triple-balance beam to measure mass. A triple-beam balance gets its name because it has three beams that allow you to move known masses along the beam. Here is a picture of a triple beam balance.
Answer: 
Hz
Explanation: Recall the formula for the speed of light is
where 
is the speed of light,
is the wavelength, and 
is the frequency. Assuming this takes place in a vacuum, 
m/s. Now we can solve for frequency
(rounding to 3 sig figs)
Thus, the frequencyis Hz.
