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

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:

$E_{1}=\frac{1}{2} m u^{2}$

Final kinetic energy of blood is determine by the relation:

$E_{2}=\frac{1}{2} m v^{2}$

Applying work-energy theorem,

Work done = Change in kinetic energy

W = E₂ - E₁

$W=\frac{1}{2} m (v^{2}-u^{2})$

Substitute the suitable values in the above equation.

$W=\frac{1}{2}\times0.08\times (1^{2}-0^{2})$

W = 0.04 J