Thinking about the topics in this chapter, here is an earth analogy. in big cities, you can see much farther on days without smog. why?

Now that the first three steps have been explained, identify the next three steps, in order. calculate the magnitude of r sum vector components calculate a and b magnitudes calculate the direction of r, calculate x,y components step 4 step 5 step 6

As part of your daily workout, you lie on your back and push with your feet against a platform attached to two stiff springs arranged side by side so that they are parallel to each other. when you push the platform, you compress the springs. you do an amount of work of 79.0 j when you compress the springs a distance of 0.230 m from their uncompressed length. (a) what magnitude of force must you apply to hold the platform in this position? (b)how much additional work must you do to move the platform a distance 0.230 m farther? (c) what maximum force must you apply to move the platform a distance 0.230 m farther?

How many excess electrons must be present on each sphere if the magnitude of the force of repulsion between them is 4.57×10−21 newtons?