What self assessments can you do to determine whether you are at risk for back pain?

The free body diagram shows a box being pulled to the left up a 25-degree incline. the magnitude of the normal force is

Although longitudinal waves can travel through all media types what is the disadvantage of this type of wave transmission? a) he efficiency of he wave transmission is greatly diminished as the media becomes less dense b) the oscillation of one set of particles has a huge impact on neighboring particles c) particles become too close together as they bump into each other making it more likely to hit other particles down the line

If the chemical properties of a substance remain unchanged and appearance or shape of a substance changes it is called a ?