A 4.20-kg object is attached to a vertical rod by two strings as shown in the figure below. The object rotates in a horizontal circle at constant speed 6.85 m/s. 2.00 m 3.00 m m 2.00 m (a) Find the tension in the upper string. Your response is within 10% of the correct value. This may be due to roundoff error, or you could have a mistake in your calculation. Carry out all intermediate results to at least four-digit accuracy to minimize roundoff error. N (b) Find the tension in the lower string. Your response differs from the correct answer by more than 10%. Double check your calculations. N