The quantity t1/2=τ ln 2 is called the half-life of an exponential decay, where τ=rc is the time constant in an rc circuit. the current in a discharging rc circuit drops by half whenever t increases by t1/2. for a circuit with "r=1.0 kω and c=4.0 μf, if the current is 6.0 ma at t=4.0 ms", at what time (in ms) will the current be 3.0 ma?

One soccer player (a) is moving at 4 km/h when she kicks the ball while another soccer player (b) is moving at 8 km/h. what statement accurately compares their kinetic energy if they have the same mass? a) both soccer players have the same kinetic energy. b) player b has twice the kinetic energy of player a. c) player b has four times the kinetic energy of player a. d) their kinetic energy can't be compared without knowing their mass.