Solution of task 7.8.5 from the collection of Kepe OE

Solution of task 7.8.5 from the collection of Kepe OE

7.8.5
The point moves along the circle. Determine the radius of the circle if, at a time when the velocity v = 10 m / s, the acceleration vector and the velocity vector, which is 1.2 m / s modulo 1.20 / s, form an angle of 30 °. (Answer 167)