Two 125 kg bumper cars are moving toward each other in opposite directions. car x is moving at 10 m/s and car z at –12 m/s when they collide head–on. if the resulting velocity of car z after the collision is 10 m/s, what is the velocity of car x after the collision?
–12 m/s
–10 m/s
10 m/s
12 m/s

What properties of a moving object are used in determining the object's energy of motion

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?

Amichelson interferometer operating at a 600 nm wavelength has a 3.02-cm-long glass cell in one arm. to begin, the air is pumped out of the cell and mirror m2 is adjusted to produce a bright spot at the center of the interference pattern. then a valve is opened and air is slowly admitted into the cell. the index of refraction of air at 1.00 atm pressure is 1.00028.how many bright-dark-bright fringe shifts are observed as the cell fills with air?