試題詳解

7.A certain pendulum consists of a 1.5-kg mass swinging at the end of a string (length = 2.0 m). At the lowest point in the swing the tension in the string is equal to 20 N. To what maximum height above this lowest point will the mass rise during its oscillation? Take g = 10 m/s²
(A)77 cm
(B)50 cm
(C)63 cm
(D)33 cm
(E)95cm