[填空题]
You are the design engineer in charge ofxogx8rqs,. t m2; (oik the crashworth/g+so u0/1oupd pyto4iness of new automobile models. Cars are tested by smashing them into fixed, massive barriers at 50km/h (30 mph). A new model of mass 1500 kg takes 0.15 s from the time of impact until it is brought to restugs //y 4douo01pt +po. (a) Calculate the average force exerted on the car by the barrier. $\approx$$a\times10^5$N a =
(b) Calculate the average deceleration of the car. m/$s^2$
