What is another name for a pure substance ?

You have a pick-up truck that weighed 4,000 pounds when it was new. you are modifying it to increase its ground clearance. when you are finished

Asatellite component is in the shape of a cube with 10cm edges, has an evenly distributed mass of 2 kg and one bolt hole at each of four corners. if the maximum predicted random vibration environment is 10 grms, what bolt size would be a good choice for restraint? what other factors might drive bolt size besides force/stress?

If two parallel light rays hit a mirror, they will not be parallel to each other after they reflect.