110-kg motorcycle and rider are traveling at 20 m/s. the rider notices a wreck ahead, applies the brakes, and manages to stop the car in 12 meters. using work-energy, find the force of friction used to stop the car. (pick the answer closest to the true value.)

a. 37,500 newtons
b. 3,375 newtons
c. 337 newtons
d. 450 newtons
e. 2,250 newtons

When you turn on a battery-operated device, an electrical circuit is

Air is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. air enters the heat exchanger at 95 kpa and 20°c at a rate of 0.6 m^3/s. the combustion gases (cp = 1.10 kj/kg°c) enter at 160°c at a rate of 0.95 kg/s and leave at 95°c. determine the rate of heat transfer to the air and its outlet temperature.

Click the game tab at the bottom of the simulation and select level 1. (there is no seesaw balance for this part of the activity.) balance the first equation, and click check to see if you got it right. if you can’t balance it in the first try, you can try again. work through the five equations for level 1. click continue to go on to level 2, and later level 3. each level is more difficult than the one before. keep trying until all the equations are balanced. in one or two sentences, describe how you did in the balancing game. in a few more sentences, explain one strategy you learned for balancing more complex equations.