Question

The average marathon runner can complete the 42.2-km distance of the marathon in 3 h and 30 min. If the runner's mass is 85 kg, what is the runner's average kinetic energy during the run

Answer 1

Answer:

the runner's average kinetic energy during the run is 476.96 J.

Explanation:

Given;

mass of the runner, m = 85 kg

distance covered by the runner, d = 42.2 km = 42,200 m

time to complete the race, t = 3 hours 30 mins = (3 x 3600s) + (30 x 60s)

                                                                               = 12,600 s

The speed of the runner, v = d/t

                                          v = 42,200 / 12,600

                                          v = 3.35 m/s

The runner's average kinetic energy during the run is calculated as;

K.E = ¹/₂mv²

K.E = ¹/₂ × 85 × (3.35)²

K.E = 476.96 J

Therefore, the runner's average kinetic energy during the run is 476.96 J.