- 1 12 At 45 Latitude The Gravitational Acceleration As A Function Of Elevation Z Above Sea Level Is Given By G A Bz 1 (137.39 KiB) Viewed 42 times
1-12 At 45° latitude, the gravitational acceleration as a function of elevation z above sea level is given by g = a - bz, where a = 9.807 m/s² and b = 3.32 x 106 s ². Determine the height above sea level where the weight of an object will Joseph L decrease by 0.3 percent. Answer: 8862 m 1-13 What is the weight, in N, of an object with a mass of 200 kg at a location where g = 9.6 m/s²? 1-14 A 3-kg plastic tank that has a volume of 0.2 m³ is filled with liquid water. Assuming the density of water is 1000 kg/m³, determine the weight of the combined system. 1-15E The constant-pressure specific heat of air at 25°C is 1.005 kJ/kg-°C. Express this value in kJ/kg-K, J/g °C, kcal/ kg-°C, and Btu/lbm-°F. 1-16 A 3-kg rock is thrown upward with a force of 200 N at a location where the local gravitational acceleration is 9.79 m/s². Determine the acceleration of the rock, in m/s². 1-18 A 4-kW resistance heater in a water heater runs for 3 hours to raise the water temperature to the desired level. Determine the amount of electric energy used in both kWh and kJ. 1-19E A 150-lbm astronaut took his bathroom scale (a spring scale) and a beam scale (compares masses) to the moon where the local gravity is g = 5.48 ft/s². Determine how much he will weigh (a) on the spring scale and (b) on the beam scale. Answer: (a) 25.5 lbf, (b) 150 lbf 1-20 The gas tank of a car is filled with a nozzle that discharges gasoline at a constant flow rate. Based on unit considerations of quantities, obtain a relation for the filling time in terms of the volume V of the tank (in L) and the discharge rate of gasoline V (in L/s). 1-21 A pool of volume V (in m³) is to be filled with water using a hose of diameter D (in m). If the average discharge velocity is V (in m/s) and the filling time is t (in s), obtain a relation for the volume of the pool based on considerations of quantities involved. 1-22 The weight of bodies may change somewhat from one location to another as a result of the variation of the gravitational acceleration g with elevation. Accounting for this variation using the relation in Prob. 1-12, determine the weight of an 80-kg person at sea level (z = 0), in Denver (z = 1610 m), and on the top of Mount Everest (z = 8848 m). 1-23E A man goes to a traditional market to buy a steak for dinner. He finds a 12-oz steak (1 lbm 5 16 oz) for $5.50. He then goes to the adjacent international market and finds a 300-g steak of identical quality for $5.20. Which steak is the better buy? 1-24E What is the weight of a 1-kg substance in N, kN, kg-m/s2, kgf, lbm-ft/s2, and lbf? 1-25 Consider the flow of air through a wind turbine whose blades sweep an area of diameter D (in m). The average air velocity through the swept area is V (in m/s). On the bases of the units of the quantities involved, show that the mass flow rate of air (in kg/s) through the swept area is proportional to air density, the wind velocity, and the square of the diameter of the swept area. 1-26 The drag force exerted on a car by air depends on a dimensionless drag coefficient, the density of air, the car velocity, and the frontal area of the car. That is, FD = function (CDrag, Afront, p, V). Based on unit considerations alone, obtain a relation for the drag force.