g = Local acceleration of gravity, m/s2 (ft/sec2) z = Elevation above some datum, m (ft) What is the unit of the constant? ii) The air drag (D) on a baseball thrown by a pitcher at a speed V in still air is given by D = CD S V2 /2, ρ where, CD = Dimensionless drag coefficient, = Air density, ρ S = Projected area of the ball Find the unit of drag. N.m/kg , N.m N /m2 , N m/s , kg /m N.m/kg , N SOLUTION (d) – Given, With units of To get unit of force in the numerator and units of mass in the Bernoulli’s equation with denominator by dividing the velocity and elevation by So the unit of constant m.kg/N.s2. are in SI. N.m/kg Given the air drag (D) on a ball D = CD ρ S V2 /2, Where the terms have the following dimensions, Drag coefficient, CD = Dimensionless Air density, = kg/m3 ρ Projected area of the ball, S = m2 Velocity of ball, V = m/s
g = Local acceleration of gravity, m/s2 (ft/sec2) z = Elevation above some datum, m (ft) What is the unit of the constant? ii) The air drag (D) on a baseball thrown by a pitcher at a speed V in still air is given by D = CD ρ S V2 /2, where, CD = Dimensionless drag coefficient, ρ = Air density, S = Projected area of the ball Find the unit of drag. N.m/kg , N.m N /m2 , N m/s , kg /m N.m/kg , N SOLUTION – (d) Given, With units of To get Bernoulli’s equation with unit of force in the numerator and units of mass in the denominator by dividing the velocity and elevation by m.kg/N.s2. So the unit of constant are N.m/kg in SI. Given the air drag (D) on a ball D = CD ρ S V2 /2, Where the terms have the following dimensions, Drag coefficient, CD = Dimensionless Air density, ρ = kg/m3 Projected area of the ball, S = m2 Velocity of ball, V = m/s