If guy wires are used to stabilize a tower, what is the minimum number of wires necessary? Imagine what would happen if you only used one or two wires. The guy wires work together so that the tower does not fall in any direction. As long as there are no external forces and the wires are equally spaced, each of the wires should experience an equal amount of tension. The tension in each guy wire can be expressed as a vector force. It is important that values are given for each force so that engineers can make informed decisions about the necessary strength of guy wires and their support mechanisms.

Amoving electron has kinetic energy k1. after a net amount of work w has been done on it, the electron is moving one-quarter as fast in the opposite direction. (a) find w in terms of k1. (b) does your answer depend on the final direction of the electron's motion?

The force needed to overcome static friction is usually less than that needed to overcome kinetic friction.true or false?

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".