The attached graph represents the tension in the cable as a pendulum swings through a complete cycle, but I don't understand how it works out like this.
The explanation states that at equilibrium, "the tension must offset the entire weight as well as counterbalance the centripetal force."
So if they're saying T = mg and T = mv/r^2, then mg = mv/r^2. The way I understand it is that the tension the bob feels is mv/r^2, and the tension felt by the center of that centripetal force is mg. In other words, I thought they canceled each other out at equilibrium, so I don't see how tension is greatest here.
"However, when the bob is at its highest point (and motionless), the tension is reduced, because there is no centripetal force to offset. Only the cosine portion of the weight must be offset."
Why would centripetal force be gone at the highest point?
The explanation states that at equilibrium, "the tension must offset the entire weight as well as counterbalance the centripetal force."
So if they're saying T = mg and T = mv/r^2, then mg = mv/r^2. The way I understand it is that the tension the bob feels is mv/r^2, and the tension felt by the center of that centripetal force is mg. In other words, I thought they canceled each other out at equilibrium, so I don't see how tension is greatest here.
"However, when the bob is at its highest point (and motionless), the tension is reduced, because there is no centripetal force to offset. Only the cosine portion of the weight must be offset."
Why would centripetal force be gone at the highest point?
