A ball is dropped over the edge of a building. a.) If the building is 200 meters tall how long does it take to hit the ground? b.) How fast is the ball moving right before it hits the ground?

The first-order reaction a→2b+c has rate constant 0.538 s−1. if the initial concentration of a is 0.867 mol l−1, what is the half-life of the reaction in seconds? remember to use correct significant figures in your answer (round your answer to the nearest hundredth). do not include units in your response.