An airplane is accelerating forward due to a force of 3320 newtons acting 30 on it. then it encounters wind resistance that exerts a backward force of 550 newtons. what is the net force, in newtons, acting on the airplane?

Two resistors r1 and r2 may be connected either in series or parallel across an ideal battery with emf ε. we desire the rate of energy dissipation of the parallel combination to be 8.75 times that of the series combination. if r1 = 105 ω, what are the (a) smaller and (b) larger of the two values of r2 that result in that dissipation rate?