the first time you hear a sound it took 2.6seconds and takes 7.1 seconds for you to hear an echo the speed of sound is 340m. s how wide is the river

Using the given data table, calculate the acceleration of the skateboarder. you can use either form of the equation below?

What are atoms of the same element with varying number of neutrons

Does anyone know how to solve this problem? i really need . i made an attempt but i just cant get it. a metal rod is 25.000 cm long at 25.0 degrees celsius. when heated to 102.0 degrees celsius, it is 25.054 cm long. what is the coefficient of linear expansion for this metal.