Achild on a spinning playground ride is 0.36 m from the center of the ride. the centripetal force on the child is 19 n. what is the mass of the child if the child has a tangential speed of 0.54 m/s?

The drag force, fd, imposed by the surrounding air on a vehicle moving with velocity v is given by fd = cdaρv 2/2 where cd is a constant called the drag coefficient, a is the projected frontal area of the vehicle, and ρ is the air density. an automobile is moving at v = 80 kilometers per hour with cd = 0.28, a = 2.3 m2, and ρ = 1.2 kg/m3.