# A 5-kg piston in a cylinder with a diameter of 100 mm is

Chapter 1, Problem 101HP

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QUESTION:

Problem 101HP

A 5-kg piston in a cylinder with a diameter of 100 mm is loaded with a linear spring and the outside atmospheric pressure is 100 kPa, as shown in Fig. P1.101. The spring exerts no force on the piston when it is at the bottom of the cylinder, and for the state shown, the pressure is 400 kPa with volume 0.4 L. The valve is opened to let some air in, causing the piston to rise 2 cm. Find the new pressure.

FIGURE P1.101

QUESTION:

Problem 101HP

A 5-kg piston in a cylinder with a diameter of 100 mm is loaded with a linear spring and the outside atmospheric pressure is 100 kPa, as shown in Fig. P1.101. The spring exerts no force on the piston when it is at the bottom of the cylinder, and for the state shown, the pressure is 400 kPa with volume 0.4 L. The valve is opened to let some air in, causing the piston to rise 2 cm. Find the new pressure.

FIGURE P1.101

Solution 101HP

Step 1 of 5:

A piston inside a cylinder is connected to a linear spring. We are going to find the final pressure inside the cylinder when the valve is opened.

The diameter of the piston D = 100 mm = 0.1 m

The radius of the piston r = 0.05 m

The mass of the piston m = 5 kg

The acceleration due to gravity g = 9.81 m/s2

The atmospheric pressure P0 = 100 kPa