Answer to Question #157746 in Physics for Dr. Horus

Question

A 2.5kg mass tied to a string is whirled around a horizontal circle of radius 1.7m. The tension in the string is 35.7N and the string is inclined at 60° above the horizontal. Calculate the speed at which the stone moves round the circle.

Answer 1

According to the second Newton's law $F=ma$. So, we have

$N\cos60°=m\frac{v^2}{r} \to v=\sqrt{\frac{N\cos60°\cdot r}{m}}=$

$=\sqrt{\frac{35.7\cdot\cos60°\cdot 1.7}{2.5}}\approx3.5(m/s)$ . Answer