# Introduction To Physical Science

## Chapter 12: Forces and Fluids

### Forces and Fluids

 1 __________ is the force per unit area applied on the surface of an object. Need a Hint? A) Gravity B) Mass C) Weight D) Pressure 2 What determines whether an object will sink or float? Need a Hint? A) whether gravity acts on the object in the fluid B) whether a buoyant force acts on the object C) the direction of the buoyant force on the object D) whether the buoyant force is larger than the object's weight 3 The supporting force exerted by a fluid on an object immersed in it is called __________. Need a Hint? A) buoyant force B) density C) viscosity D) lift 4 Bernoulli's principle states that as the velocity of a fluid __________, the pressure exerted by the fluid __________ . Need a Hint? A) increases, increases B) decreases, decreases C) increases, decreases D) decreases, increases 5 An object weighing 50 kg is floating in a fluid. What is the buoyant force of the fluid on the object? Need a Hint? A) > 50 kg B) < 50 kg C) Not enough information is given. D) 50 kg 6 At what depth is the buoyant force on a submerged object the greatest? Need a Hint? A) The buoyant force on a submerged object is the same at any depth. B) at the surface C) on the ocean floor D) at sea level 7 Pressure is defined as __________. Need a Hint? A) pressure = area/force B) pressure = mass/acceleration C) pressure = force/area D) P1 = P2 8 What two things must you know to calculate the pressure exerted on a surface? Need a Hint? A) the force that is applied and the density of the surface B) the area over which a force is applied and the mass of the object applying the pressure C) the force and the area over which it is applied D) the force and the weight of the object 9 As the height of a fluid above a surface __________, the pressure exerted by the fluid on that surface __________. Need a Hint? A) increases, increases B) decreases, increases C) increases, decreases D) The pressure exerted by a fluid on a surface is unaffected by the height of the fluid. 10 A __________ is any substance that has no definite shape and can flow. Need a Hint? A) gas B) fluid C) liquid D) plasma 11 Which of the following is NOT a fluid? Need a Hint? A) pure oxygen B) water C) steam D) ice 12 If a cube is submerged in water, where on the cube is the pressure exerted by the water the greatest? Need a Hint? A) The pressure is equal on all sides of a cube. B) on the bottom C) on the sides D) on the top 13 An instrument called a(n) __________ is used to measure atmospheric pressure. Need a Hint? A) barometer B) thermometer C) odometer D) galvanometer 14 According to Pascal, pressure applied to a fluid __________. Need a Hint? A) increases as it moves through the fluid B) fluctuates as it is transmitted throughout the fluid C) decreases as it moves through the fluid D) is transmitted unchanged throughout the fluid 15 In which direction is pressure by a fluid exerted on an object that is submerged in it? Need a Hint? A) upward B) parallel to the vertical surfaces, perpendicular to the horizontal surfaces C) downward D) perpendicular to all surfaces of the object 16 The same force is applied to two different objects. The area over which the force is applied to object A is twice as large as the area over which the force is applied to object B. Which of the following statements is true of these objects? Need a Hint? A) If the same force is used, the pressure exerted on the objects is the same. B) The pressure applied to object A is equal to the square of the pressure applied to object B. C) The pressure exerted on object B is twice as great as the pressure exerted on object A. D) The pressure exerted on object A is twice as great as the pressure exerted on object B. 17 A(n) __________ uses a fluid to increase an applied force. Need a Hint? A) compound machine B) simple machine C) wheel and axle D) hydraulic system 18 What is the approximate pressure exerted on your body by the atmosphere at sea level? Need a Hint? A) 1,000 Pa B) 10,000 Pa C) 100 Pa D) 100,000 Pa 19 How does Bernoulli's principle explain how airplanes fly? Need a Hint? A) Air pressure is greater below the wings, creating lift. B) Air pressure is greater on the top of the wings, creating lift. C) The air pressure on top of the wing is equal and opposite to the air pressure on the bottom, creating a balanced upward force. D) The backward force exerted by an engine creates an equal and opposite push, resulting in lift. 20 Archimedes' principle states that __________. Need a Hint? A) the buoyant force on an object is greater than the weight of the fluid it displaces B) the buoyant force on an object is equal to the weight of the fluid it displaces C) when the speed of a fluid increases, the pressure exerted by the fluid decreases D) pressure applied to a fluid is transmitted unchanged throughout the fluid