試題詳解

3.The speed of a particle moving in a circle 2.0 m in radius increases at the constant rate of 6.0 m/s. At an instant when the magnitude of the total acceleration is 10.0 m/s, what is the speed of the particle?
(A)3.0 m/s
(B)4.0 m/s
(C) 5.0 ml/s
(D)6.0 m/s
(E)8.0 m/s