A rock contains 25% of it's parent isotope potassium - 40. The other 75% is now the daughter isotope. The half - life of potassium - 40 is 1.3 billion years. Determine the absolute age of the rock. In the previous problem we determine that 2 half - lives have passed. Write out the next step and the answer to the problem.​

Steelhead trout migrate up stream to spawn.occasionally they need to leap up small waterfalls to continue their journey. fortunately, steelhead are remarkable jumpers, capable of leaving the water at a speed of 8.0 m/s. a. what is the maximum height a steelhead trout can jump? b.leaving the water at 8.0 m/s, the trout lands on top of the water fall 1.8 m high. how long was it in the air?