Circular motion 5. An object moving at constant speed requires 6 s to go once around a circle with a radius of 4m. What is the constant speed of the object? What is the magnitude of the instantaneous acceleration of the particle during this time? Ans: v=4.18 m/s; a-ap-4.37 m/s² A particle moves at a constant speed in a circular path with a radius of 2 cm. If the particle makes four revolutions each second, calculate: a) the speed of the particle; b) the magnitude of its acceleration. Ans: v=0.5 m/s; a-acp-12.5 m/s² 7. A particle moves along a circular path having a radius of 2m. At the instant when the speed of the particle is equal to 3 m/s and changing at the rate of 5 m/s², what is the magnitude of the total acceleration of the particle? Ans: acp 4.5 m/s²; a-6.72 m/s² 8. The speed of a particle moving in a circle 2 m in radius increases at the constant rate of 4.4 m/s². At the instant when the magnitude of the total acceleration is 6 m/s², what is the speed of the particle? Ans: v=2.85 m/s