Một ô tô A chạy đều trên 1 đường thẳng với vận tốc 40km/h. Một ô tô B chạy ngược chiều với vận tốc 60km/h. Tính vận tốc ô tôt B so với ô tô A

7.45 a student is interested in the aerodynamic drag on spheres. she conducts a series of wind tunnel tests on a 10-cm-diameter sphere. the air in the wind tunnel is at 50 â°c and 101.3 kpa. she presents the results of her tests in the form of a correlation, đť’ź = 0.0015v1.92, where đť’ź is the drag force in newtons and v is the velocity in m/s. another student realizes that the results would have been more effectively presented in terms of dimensionless parameters, say, î  1 = f (î  2) = c î  a2 , where î  1 and î  2 are dimensionless parameters and c and a are constants. what are the most appropriate dimensionless parameters (î  1 and î  2) and the corresponding values of c and a? what would be the drag on a 2-cm-diameter sphere placed in a 1-m/s, 20 â°c water stream?