1. The total cross-sectional area of the load-bearing calcified portion of the two forearms bones (radius and ulna) is approximately 2.16cm^2. During a car crash, the forearm is slammed against the dashboard. Tha arm comes to rest from an initial speed of 81.9km/h in 7.72 s. If the arm has an effective mass of 1.88kg what is the compressional stress on the arm? Answer in units of Pa. 2. Stress=F/A , additional F=ma Vf=Vo+at 3. Conversions A=2.16cm^2*1m^2/10^4cm =2.16e-4m^2 Vo=81.9km/h*(1hr/60mins)(1min/60s)(1000m/1km) =22.75m/s F=ma a=(Vf-Vo)t=-2.94689. I assumed I could make it positive since the problem's context is in forward motion not retardation. F=1.88kg*2.94689 =5.540kg*m/s^2 P=F/A P=5.540kg*m/s^2/2.16e-4 =25.648.8677N/m^2= same in Pa. I feel like I put in the appropriate conversions and formulas but when I plug in the answer, I'm told I am wrong. Does it have to do with the fact that it mentions "two forearm bones" in the beginning? If it is, where do I half the cross sectional area? I hope I'm not too far off.