✔ 最佳答案
1. You should know that the tape can only examine halfperiod of the motion.
The dots are closely packed initially, then the dots are spacedwider and wider until the bob reaches the lowest point. This is because the bobis accelerating towards the equilibrium position. After that, the dots becomeless and less spaced. And at last, the dots are closely packed. It shows thatthe bob is accelerating in the opposite direction after it passes through theequilibrium position.
2. The x-t, v-t and x-a graphs are trigo functions. Thedisplacement leads the velocity by 90˚ and the velocity leads the accelerationby 90˚. It shows that displacement leads acceleration by 180˚ and hencedisplacement and acceleration are always in the opposite direction.
3. The simple pendulum is accelerating towards theequilibrium position. Acceleration decreases in magnitude with the distancebetween the bob and the equilibrium position. And the velocity is the greatestwhen the bob is in the lowest point.
The trolley is accelerating uniform along the plane. Thevelocity is increasing uniformly.
