There is a spring attached to the door on Elijah’s front porch. Elijah opens
the door stretching the spring (1). After walking through the doorway (2),
Elijah lets go of the door, and the spring contracts, pulling the door shut (3).
Describe an energy transformation that took place in each in each of the
numbered events above.

Write the chemical formula for a compound that is made of an element from group 1 and an element from group 17

Ajet plane is speeding down the runway during takeoff. air resistance is not negligible. identify the forces on the jet.

You exhale co2 which is produced during cellular respiration.  co2 combines with the water in your blood's plasma to make up one half of the body's most important buffer pair, carbonic acid.  the more physical activity you engage in, the more co2 your body is producing.  you can see this by putting some of the cabbage indicator in a glass and then blowing bubbles into it through a straw.  can you see a change in the color of the indicator?