Speed = Distance/Time = 100 km / 4 hours = 100/4 km per hour = 25 kph
Answer:
Work is done by the heart on the blood during this time is 0.04 J
Explanation:
Given :
Mass of blood pumped, m = 80 g = 0.08 kg
Initial speed of the blood, u = 0 m/s
Final speed of the blood, v = 1 m/s
Initial kinetic energy of blood is determine by the relation:

Final kinetic energy of blood is determine by the relation:

Applying work-energy theorem,
Work done = Change in kinetic energy
W = E₂ - E₁

Substitute the suitable values in the above equation.

W = 0.04 J
The answer for this is b 3.500.000j