if you clap your hands and hear an echo from a distant wall 0.75 seconds later, how far away is the wall? assume the speed of sound is 343 m/s.

Many machines- including inclined planes such as ramps- increase the strength of the force put into the machine but decrease the distance over which the force is applied.

Give an example in which the electrical energy changes to light energy

Suppose that f : rn → rm and that a ∈ k, where k is a connected subset of rn . suppose further that for each x ∈ k there exists a δx > 0 such that f(x) = f(y) for all y ∈ bδx (x). prove that f is constant on k; that is, f(x) = f(a) for all x ∈ k