While on a train you are holding a string with a ball

Question

Solve the all parts of following problem given below:

Problem: While on a train, you are holding a string with a ball attached to it. At first, the train's velocity is constant and the string is vertical. When the train changes direction, while going around a curve with a radius of 260 m, you measure the angle between the string and the vertical to be 28.0°. The ball has a mass of 1.00 kg, and we will use g = 10 m/s².

Part A: The speed of the train is constant during this time. What is that speed?

Part B: What is the tension in the string while the train is going around the curve?

I need help to find the tension in the string while the train is going around the curve.