Andy has a remote-controlled car which he uses primarily to annoy the family cat. He has found that the cat’s annoyance is maximized for motion which can be parametrized as x(t) = 0.5t^3 – 3t, where x is in meters and t is in seconds. Calculate the position at t=3.1s in meters. Calculate the acceleration at t=2.3s (m/s2). At what time is the instantaneous velocity zero?

Sally turns on her cellular telephone to speak to her friend who is located thousands of miles away. which of the following best describes how such a telephone is able to transmit and receive information? a. the cellular telephone transmits, receives, and encodes information using only sound waves. b. the cellular telephone transmits, receives, and encodes information using only electromagnetic waves. c. the cellular telephone transmits information by electromagnetic waves to a receiver which then encodes them and produces sound. d. the cellular telephone transmits information by sound waves to a receiver which then encodes them and produces electromagnetic waves.