Answer to Question #91386 in Mechanics | Relativity for Stuart

Question

The girl is swinging a conker on a string at a steady speed in a circular path horizontally above her head
What force contribute to the centripetal force in order to keep the conker in its circular path

Answer 1

Only two forces act on the conker: the force of gravity and the centripetal force (the force of tension of the string). In this case, while the conker is in the horizontal plane, the string cannot be located in the horizontal plane. Along it is directed the force of tension of the string, which is so large that its vertical component, directed upwards, compensates for all the force of gravity acting on the conker, directed downwards. In this case, the horizontal component of the tension of the string completely determines the uniform movement around the circular path. Horizontal component $F$ can be calculated using the uniform circular motion formula [https://en.wikipedia.org/wiki/Circular_motion#Uniform_circular_motion]

$$F = \frac{mv^2}{r},$$

where $v$ is the constant absolute value of speed of conker, $r$ is the radius of circle path, $m$ is the mass of conker.