When a tuning fork vibrates over an open pipe and the air in the pipe st21 to vibrate, the vibrations in
the tube are caused by
a. resonance.
b. reinforcement.
c. harmonics.
d. beats.

The coefficient of friction is a number that represents the resistance to sliding between two in contact with one another.

Which of these questions might a character ask if the conflict is man versus self? a. which path should i take to better myself? b. which boulder will be too heavy for me to carry? c. which friend is going to ditch me today? d. all of the above

The field between two charged parallel plates is kept constant. if the two plates are brought closer together, the potential difference between the two plates either a) decrease b) does not change c) increase?