The free body diagram below shows the forces acting on a bicycle as the rider pedals to the right. The vectors are not drawn to scale. The bicycle has aweight of 800 N and a pedaling force of 250 N. As it moves, it encounters 75 N of air resistance. What is the net force on the bicycle in the x-direction?

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?