In designing circular rides for amusement parks, mechanical engineers must consider how small variations in certain parameters can alter the net force on a passenger. consider a passenger of mass m riding around a horizontal circle of radius rat speed v. what is the variation df in the net force magnitude for(a) a variation dr in the radius with ν held constant,(b) a variation dv in the speed with r held constant, and(c) a variation dt in the period with r held constant?