Problem 13 in chapter 4 of the Giancoli Physics book askswhat the max and min forces would be acting on a cable holdingan elevator (4850kg) at an acc. of .0680g. Cramster's answer eventually sets up thisequation; FTmin =m (-a +g) =4850(-.0680+1)g This +1 is placed in the equation for both the max andthe min and I really dont know where it came from or why. Cramster's answer eventually sets up thisequation; FTmin =m (-a +g) =4850(-.0680+1)g This +1 is placed in the equation for both the max andthe min and I really dont know where it came from or why. This +1 is placed in the equation for both the max andthe min and I really dont know where it came from or why.
Explanation / Answer
Ok, it took a minute but i think i figured it out. At first i looked at the acceleration as .0680 m/s^2. But, theacceleration isn't given directly in meters per second per second.It's a relative acceleration. (Relative to the acceleration due togravity) It's given as .0680 g...which means it's 680ten-thousandths of the value for g. (9.8 meters per second persecond). So, what they're doing in this step: =4850(-.0680 +1)g is factoring out the gravitational constant g.4850(-.0680g+g)=4850(-.0680+1)g. It's just factoring. I hope that makes sense. If it doesn't, feel free to say soand i'll try to clarify it.