PY 211 North Carolina State University Module 16

Problem 7 To maintain a constant speed, the force provided by a car's engine must equal the drag force plus the force of friction of the road (the rolling resistance). The density of air g A. What are the drag forces in newtons at 79 km/h and 106 km/h for a Toyota Camry? (Drag area = 0.70 m2 and drag coefficient = 0.28.) B. What are the drag forces in newtons at 79 km/h and at 106 km/h for a Hummer H2? (Drag area = 2.44 m2 and drag coefficient = 0.57.) Problem 8 A spherical raindrop 2.3 mm in diameter falls through a vertical distance of 4600 01. Take the cross- sectional area of a raindrop = m2, drag coefficient = 0.45, density ofwater to be 1000 kg/m3, and density of air to be 1.2 kg/m3. A, Calculate the speed a spherical raindrop would achieve falling from 4600 m in the absence of air drag. B. What would its speed be at the end of4600 m when there is air drag? (Note that the raindrop will reach terminal velocity after falling about 30 m.)