What do scientists know about the future of the universe? what dark matter is made of
why the expansion of the universe is accelerating
that stars will eventually burn out causing the universe to become cold and dark
that galaxies spin much slower than they should based on visible matter

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)

Give one example to show that when substances are mixed, it may result in a chemical or a physical change depending on the conditions.

The field between two charged parallel plates is kept constant. if the two plates are brought closer together, the potential difference between the two plates either a) decrease b) does not change c) increase?