Which of the following best defines "medium of exchange"?
a. something with a fixed value that we use for exchange
b. a way to determine what is the best deal
c. the average value exchange of a single good or service
d. a monetary rate that stays constant

Laboratory experiments, observational field studies, and model-building are all examples of different forms of scientific investigations.  in what way do laboratory experiments primarily differ from other forms of scientific investigations?   a.  a laboratory experiment is the only accepted form of investigation within the scientific community.  b.  studies about how things behave in nature or studies involving very large objects are best answered through laboratory experiments.  c.  laboratory experiments involve the identification and control of variables.  d.  data can only be generated through laboratory experiments, not other forms of investigation.

Aman throws a football straight into the air. as it rises, it slows down. which type of energy is the football gaining?

A20 cm long spring is attached to a wall. the spring stretches to a length of 22 cm when you pull on it with a force of 100 n. what is the spring constant