Which is evidence that scientists use to support the big bang theory?
a.
earth is the only planet with permanent liquid water on its surface.
b.
most galaxies are moving away from each other.
c.
most orbits have an elliptical shape.
d.
the outer planets are mostly composed of hydrogen and helium.

When you drop a pebble from height a it reaches the ground with speed v if there is no air resistance. from what height should you drop it so it will reach the ground with three times the speed? (a) 9m (b) 3m (c) 6m (d) 18m

Animals respond in various ways to stimuli detected through their senses. some of these responses are stimulated by the presence of danger. which of these animal responses is the best example of a response to an immediate threat? a) a rooster crows every morning at the first sign of light. b) as something approaches an octopus, it shoots a cloud of ink. c) from late fall until spring, bears hibernate to preserve energy. reactivate d) a dog is getting hot in the sunlight, so he moves to a shaded area.

If a spring has a k value of 100 newtons per meter and it is stretched 0.50 meters, what is the restoring force of the spring?