A cart moving right on a frictionless track collides with a 3.0 kg cart moving left at 2.0 * m/s The 1.0 kg cart has a fina speed of 4.0 * m/s to the left.

Engineers find a new metal that is stronger than steel but much lighter. this material is also significantly cheaper than what is currently used for most aircraft, available in large quantities, and easy to manufacture. the engineers are excited because this new material will lower the costs of buying and operating airplanes for companies. what is probably the best step for the engineers to make next?

Lightning is an example of what phenomenon? a release of a large amount of energy an absorption of a large amount of energy a natural electric circuit a natural electric current

If two parallel light rays hit a mirror, they will not be parallel to each other after they reflect.