# Physics

Order Instructions/Description

1. A storage tank of negligible mass and 30m high is filled with gasoline. Please calculate the following. Use density values found in the book.
a) The gauge pressure and absolute pressure at the bottom of the tank. 7 pts
b) The force that acts on a square access hatch at the bottom of the tank that measures 0.5m x 0.5m. 7 pts
c) Given that the tank is shaped like a right circular cylinder with a height of 30 m and with a base radius of 10m. The tank is attached to a steel cable of negligible mass and immersed in water. Calculate the tension (force) in the cable before and after it is immersed in water. 7 pts

2.  The total mass of the hydrogen gas in the Hindenburg zeppelin was 18,000 kg. Assuming standard conditions, what volume did the hydrogen occupy? (This is problem 10 of chapter 4 in the textbook.) 9 pts

1. A certain part of an aircraft engine has a volume of 1.3 ft³.
a) Find the weight of the piece when it is made of iron. 7 pts
b) If the same piece is made of aluminum, find the weight and determine how much weight is saved by using aluminum instead of iron. 7 pts (This is problem 12 of chapter 4 in the textbook.)
4.  A juniper-wood plank measuring 0.25 ft by 1 ft by 16 ft is totally submerged in water.
a) What is its weight? 7 pts
b) What is the buoyant force acting on it? 7 pts
c) What is the size and the direction of the net force on it? (This is problem 26 of chapter 4 in the textbook.) 7 pts
5.  A rectangular block of ice with dimensions 2 m by 3 m by 0.2 m floats on water. A person weighing 600 N wants to stand on the ice. Would the ice be able to support the individual and not sink below the surface of the water? Validate your answer. (This is problem 30 of chapter 4 in the textbook.) 9 pts

2. The concrete sections of a certain superhighway are designed to have a length of 25.0 m. The sections are poured and cured at 10.0°C. What minimum spacing should the engineer leave between the sections to eliminate buckling if the concrete is to reach a temperature of 50.0°C? For concrete α = 12.0 x10-6(°C)-1. 9 pts

7.  A bottle containing 3 kg of water at a temperature of 20°C is placed in a refrigerator where the temperature is kept at 3°C. How much heat is transferred from the water to cool it to 3°C? (This is problem 10 of chapter 5 in the textbook.)  9 pts
8.  Suppose you have a heat engine operating between 230°C and 100°C. It achieves 20.0% of the maximum possible efficiency (Carnot Efficiency). What energy input will enable the engine to perform 12.0 kJ of work? 7 pts
9.  Water flowing over the Lower Falls in Yellowstone National Park drops 94 m. If all of the water’s energy goes to heat it, what is its temperature increase? (This is problem 16 of chapter 5 in the textbook.) 7 pts

10.  A 1,200-kg car going 25 m/s is brought to a stop using its brakes. Let’s assume that a total of approximately 20 kg of iron in the brakes and wheels absorbs the heat produced by the friction.
a) What was the car’s original kinetic energy? 7 pts
b) After the car has stopped, what is the change in temperature of the brakes and wheels? 7 pts