How fast must an object move before its length appears to be contracted to one-fourth its proper length?

What are similarities and differences between refraction, reflection, diffraction and absorption?

Diamond will scratch quartz. true or false

This is really important 1.which of the following prefixes represents the largest value? (2 points)gigahectorkilomilli2.which of the following types of graphs is best for plotting the mean, median, and mode of data? (2 points)bar graphbox-and-whiskercircle graphstem-and-leaf