Des Linden won the Boston marathon in 2018, becoming the first American woman to win since 1985. The harsh conditions (heavy rain and a headwind) led to a winning time of 2 hrs 39 minutes and 54 seconds. If she weighed 99 pounds, her average heart rate during the race was 170 beats per minute and her heart pumped 2.5 mLs of blood per kg body mass per beat, how much blood did her heart pump during the race?

3050.6 Litre .

Explanation:

Total time of heart beat = Total time of race  = 2 hrs , 39 minutes and 54 seconds

= 2 x 60 + 39 + 54/60 min

= 120 + 39 + .9 min

= 159.9 min

rate of heart beat = 170 per min

Total no of heart beat during race = 170 x 159.9

volume of blood per kg per beat = 2.5 mL per kg of weight

body weight  = 99 pounds = .4535 x 99  kg = 44.89 kg

volume of blood  per beat = 2.5 mL x 44.89 mL

= 112.225 mL .

Total required volume of blood =  112.225  x 170 x 159.9 mL

= 3050612 mL

= 3050.6 L.

at positions a, g kinetic energy is maximum.

at position d, potential energy is maximum.

0.11 m/s and 0.28 m/s should be correct