With what initial speed must a ball be thrown upward to reach a height of 39.0m and how long will the ball stay in the air?

In a voltaic cell, electrons flow from the (positive/negative) to the (positive/negative) terminal.

Achlorine atom has 17 protons and 18 neutrons. what is its mass number? what is its atomic number?

Arunner is jogging at a steady 3.6 km/hr. when the runner is 2.9 km from the finish line, a bird begins flying from the runner to the finish line at 14.4 km/hr (4 times as fast as the runner). when the bird reaches the finish line, it turns around and flies back to the runner. even though the bird is a dodo, we will assume that it occupies only one point in space, i.e., a zero-length bird. how far does the bird travel? (b) after this first encounter, the bird then turns around and flies from the runner back to the finish line, turns around again and flies back to the runner. the bird repeats the back and forth trips until the runner reaches the finish line. how far does the bird travel from the beginning? (i.e. include the distance traveled to the first encounter)