An implanted pacemaker supplies the heart with 72 pulses per minute, each pulse providing 6.0 v for 0.65 ms. the resistance of the heart muscle between the pacemaker’s electrodes is 550ω. find (a) the current that flows during a pulse, (b) the energy delivered in one pulse, and (c) the average power supplied by the pacemaker.

a) 0.11 Amp b) 0.000429 Joules c) 0.000514 watt

Explanation:

a)current

I=V/r I=6.0/550 =1.1*10^-2 A

b) energy

E= 1.1*10^-2 x (6.0) x 0.00065s(<-- remember to convert ms to seconds) = 0.000429J

C) Average power

P = (0.000429 x 72) / 60

P = 0.000514 W

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)