Question

The left side of the heart creates a pressure of 120mm Hg by exerting a force directly on the blood over an effective area of 15.0cm². What force does it exert to accomplish this?

1. 1.80 N
2. 2.40 N
3. 3.00 N
4. 4.00 N

Answer 1

The left side of the heart exerts a force of 2.40 N to create a pressure of 120 mm Hg over an area of 15.0 cm², by converting the given pressure to pascals and then using the pressure equation.

Therefore, the left side of the heart exerts a force of 24 N to create a pressure of 120 mm Hg over an area of 15.0 cm². The correct answer is option 2. 2.40 N.

Step-by-step explanation:

The question is about the force exerted by the left side of the heart when it creates a pressure of 120 mm Hg over an area of 15.0 cm². To find the force, we need to use the formula for pressure, which is pressure (P) = force (F) / area (A). The pressure given is in mm Hg, which we need to convert to N/m² (pascals) to use with the area given in cm² for the calculation.

Firstly, convert the pressure from mm Hg to N/m² by using the conversion 1 mm Hg = 133.322 Pa (or N/m²):
120 mm Hg * 133.322 Pa/mm Hg = 16000 Pa (or 16000 N/m² since 1 Pa = 1 N/m²).

Next, convert the area from cm² to m²:
15.0 cm² * (1 m/100 cm)^2 = 0.0015 m².

Now, calculate the force:
F = P * A
F = 16000 N/m² * 0.0015 m²
F = 24 N.

Therefore, the left side of the heart exerts a force of 24 N to create a pressure of 120 mm Hg over an area of 15.0 cm². The correct answer is option 2. 2.40 N.