How much work do you do when you lift a 100-N child 0.5 m?

Identify the type of synthetic material used in each object

Awoman stands a distance d from a loud motor that emits sound uniformly in all directions. the sound intensity at her position is an uncomfortable 2.0×10-3 w/m2. at a distance 2.6 times as far from the motor, what are (a) the sound intensity and (b) the sound intensity level relative to the threshold of hearing?

What are the applications of electromagnetic waves