Answer Happy

A small ball of mass m is tied to a string of length I and set rotating with negligible friction in a vertical circle. At the top of the circle, it is moving at speed v. Answer questions below in terms of m, L, v, and/or gravitational acceleration g. a. At the bottom of the circle, how fast is the ball moving? Hint for (a) The ball is moving at speed bottom= at the bottom. Hint for (b) b. As the ball moves at the speed given above, what is the tension force on the ball? The string applies a tension Thottom on the ball at the bottom. c. Assuming the speed v at the top is fast enough that the string remains taught, what is the tension force on the ball? The string applies a tension Itop on the ball at the top. = = Consider your answers in (b) and (c) above. The difference between them gives how much the tension in the string at the bottom of the circle exceeds the tension in the string at the top (it's more than by 2mg you might expect from the change in relative directions of tension force and gravitational force, because the ball speeds up as it swings down to the bottom).