</span><span><span>Ff</span>=<span>Uk</span>mg=0.45m(9.8m/<span>s2</span>)</span> Calculate the acceleration (which will be negative since it's due to the force of friction):
<span> a=<span>Fm</span></span><span>a=<span><span>(0.45)(9.8m/<span>s2</span>)m</span>m</span></span><span>a=4.41m/<span>s2</span></span>
Time to stop:<span>t=<span><span>8.55m/s</span><span>4.41m/<span>s2</span></span></span>=1.94s</span>
Now see how far they go in 1.94s with an acceleration of -4.41m/s^2:<span>x=<span>V0</span>t+<span>12</span>a<span>t2</span></span><span>x=(8.55m/s)(1.94s)+<span>12</span>(−4.41m/<span>s2</span>)(1.94s<span>)2</span>=8.29m</span>
Slope of AB=(2-3)/(1+1)=-1/2; AC=(-1-3)/(-3+1)=-4/-2=2; BC=(-1-2)/(-3-1)=-3/-4=3/4. The product of two sides that are perpendicular is -1. Slopes of AB and AC are perpendicular so angle A is a right angle. ABC is a right-angled triangle.
