Problem Solving
1. If the mass of air inside a room is 1 kg, what is the volume of the air?
2. A massless cube container holds water whose density is 1000 kg/m3. The length of the side of the cube is 7 meters. What is the mass of the water? =
3. A 10-kg piece of metal displaces 0.002 m3 of water when submerged. What is the density of the metal?
4. The pressure acting on a floating piece of wood is measured by 12345 Pascal, and its surface area is 0.6789 m2. What is the magnitude of the force in Newtons? Hint: Review Example 2 on page 292 in the textbook.
5. A boy’s height is 1.76 meters. The vertical distance from his head to his heart is measured as 0.39 m. Find the blood pressure difference between the blood pressure in the anterior tibial artery at the foot and the blood pressure in the aorta at the heart. What is the blood pressure difference between them? The density of blood is 1060 kg/m3, and the blood is assumed as being a static fluid.
6. You bought a 1 kg solid gold statue from a merchant in Italy while you are on vacation. When you get home, you decided to test if this statue is real gold or not. After submerging the gold statue in a large water container, you will measure the volume of displaced water. What is the expected volume if the statue is made of pure gold? For the density of gold, use Table 11.1 on page 290 in the textbook.
7. A traveler at the North Pole measured the temperature as -40oC. Can you convert this temperature to the Fahrenheit scale? What is the temperature on the Kelvin scale? Hint: Use the converting formula: oF = 1.8oC + 32. The relation between the Celsius scale and the Kelvin scale is K = oC + 273.15.
8. A runner who weighs 50 kg produces 500,000 J of heat for a half hour, but this heat is removed by various mechanisms inside of her body to adjust to the conditions. However, if the heat was not removed, what is the increment of temperature? The specific heat capacity of the human body is 3500 J / kg oC from Table 12.2 on page 340 in the textbook. Hint: Review Sample Question 4 in the Unit VI Lesson and Example 9 on page 340 to 341 in the textbook.
9. In order to freeze 2 kg of water at 0oC into ice at 0oC, how much heat is required? The latent heat of fusion for water L = 335,000 J / kg. Hint: Review Sample Question 5 in the Unit VI Lesson.
10. In 1965, Penzias and Wilson discovered the isotropic cosmic background radiation of the microwave and earned the Nobel Prize in 1978. The cosmic microwave background radiation is measured by 2.725 Kelvin through the entire sky. Convert this temperature into the Celsius scale as well as the Fahrenheit scale. Hint: Use the converting formula: oF = 1.8oC + 32. The relation between the Celsius scale and the Kelvin scale is K = oC + 273.15.