Question

During each heartbeat, about 80 g of blood is pumped into the aorta inapproximately 0.2 s. During this time, the blood is accelerated from restto about 1 m/s.How much work is done by the heart on the blood during this time

Answer 1

Work is done by the heart on the blood during this time is 0.04 J

Step-by-step 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:

`E_(1)=(1)/(2) m u^(2)`

Final kinetic energy of blood is determine by the relation:

`E_(2)=(1)/(2) m v^(2)`

Applying work-energy theorem,

Work done = Change in kinetic energy

W = E₂ - E₁

`W=(1)/(2) m (v^(2)-u^(2))`

Substitute the suitable values in the above equation.

`W=(1)/(2)*0.08* (1^(2)-0^(2))`

W = 0.04 J