# Homework Help: Maximum Tension and Trajectories?

1. Nov 1, 2009

### Noke2011

Maximum Tension and Trajectories????

1. The problem statement, all variables and given/known data

A rock of mass 3.3kg is tied to a string of length 1.2m. The rock is held at rest (at an angle of 25 degrees) so that the string is initially tight, and then it is released. (A) Find the speed of the rock when it reaches the lowest point of its trajectory. (B) What is the maximum tension in the string?

2. Relevant equations

T=ma

3. The attempt at a solution

Okay, so the max tension is the amount of tension that can be applied so that the string is taught, therefore T=(3.3)(9.8)=32.34N. However, my question is, if it's held taught, and the string length cannot change, wouldn't the lowest point of the trajectory be the point at which the string is held?

2. Nov 1, 2009

Re: Maximum Tension and Trajectories????

The string length will stay the same and the string will still be taught, but the angle(and therefore the x and y coordinates of the rock) will change after released.

3. Nov 1, 2009

### Noke2011

Re: Maximum Tension and Trajectories????

But how do I find the speed of the rock at this angle? I'm not sure where to begin, would the angle just be the opposite of 25 degrees?