Amena

A boy jumps from rest, straight down from the top of a cliff. He falls halfway down to the water below in 0.993 s. How much time passes during his entire trip from the top down to the water? Ignore air resistance. Pls help and explain!

A sample starts with 1000 radioactive atoms. How many half-lives have elapsed when 875 atoms have decayed? I am not sure how to solve this, please help!!

You are flying in an ultra-light aircraft at a speed of 41.4 m/s. An eagle, whose speed is 21.7 m/s, is flying directly toward you. Each of the given speeds is relative to the ground. The eagle emits a shrill cry whose frequency is 3680 Hz. The speed of s...

Write in exponential notation x*x*x*x*x*y*z

I got 0.193 half-lives. Does this answer make sense??

For b) would the answer be the same number of N atoms of X, because the box is in a perfect vacuum?