Speed can be counted in many ways, depending on the values we know, so that we can calculate the speed. Here we have a known value for tension 100 N. We also have a weight of 1kg stone whose speed we want to calculate. In this case we will use the formula for tension T = mg + ma, where we will ignore mg the expression due to the fact that we reject the influence of earth's gravity, so that we get the expression T = ma. From this expression we will extract the acceleration value and move it to the left side of the formula:
a = T/m, a - acceleration (m/s²), T - tension (N, kgm/s²), m - weight (kg), the length of the string is one meter.
a = 100(kgm/s²) / 1(kg) = 100 m/s² and the velocity is v = √a = √100 = 10 m/s.
