Which option is an example of a pure substance? A. The compound strontium oxide
B. Carbon atoms spread evenly throughout iron atoms
C. A vinegar and oil salad dressing
D. A disc of silicon with stones of germanium in it

Aball horizontally thrown from a cliff at 8m/s

Abumper car with a mass of 250 kg is traveling at a speed of 4 m/s. this bumper car collides and sticks to a second bumper car with a mass of 250 kg, which is initially at rest. what is the final speed of these two bumper cars after the collision, assuming they remain stuck together?

How to know which equation of motion to use where?explain