Answer:
a. Walking burns up more energy.
b. 1740 kJ
c. This is because more intense exercise releases a lot of energy in a short period of time, whereas, less intense energy releases it energy gradually over a long period of time.
Explanation:
a. We know energy W = Pt where P = power and t = time.
Now for walking, t = d/v where d = distance = 5.00 km and v = speed = 3.00 km/hr and P = 290 W
So, t = d/v = 5.00 km/3.00 km/hr = 5/3 hr = 5/3 × 3600 s = 6000 s
W = Pt = 290 W × 6000 s = 1740000 = 1740 kJ
Now for running, t = d/v where d = distance = 5.00 km and v = speed = 10.00 km/hr
So, t = d/v = 5.00 km/10.00 km/hr = 0.5 hr = 0.5 × 3600 s = 1800 s and P = 700 W
W = Pt = 700 W × 1800 s = 1260000 = 1260 kJ
Since walking burns up 1740 kJ and running burns up 1260 kJ, walking burns up more energy.
b. It burns up 1740 kJ
c. This is because more intense exercise releases a lot of energy in a short period of time, whereas, less intense energy releases it energy gradually over a long period of time.
