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?

Boxing gloves are padded to lessen the force of a blow. (a) calculate the force exerted by a boxing glove on an opponent’s face, if the glove and face compress 7.50 cm during a blow in which the 7.00-kg arm and glove are brought to rest from an initial speed of 10.0 m/s. (b) calculate the force exerted by an identical blow in the gory old days when no gloves were used and the knuckles and face would compress only 2.00 cm. (c) discuss the magnitude of the force with glove on. does it seem high enough to cause damage even though it is lower than the force with no glove?