Match the following vocabulary words with their definitions.
1. subsonic
the speed of an object traveling
below the speed of sound
sounds that humans can hear
2. supersonic
a phenomenon produced by the
3. audible
interference of waves at slightly different
frequencies
4. beats
the speed of an object traveling
above the speed of sound

The material that keeps its new shape after it is stretched is called?

(2) (a) you have a simple circuit that consists of only a battery (δvbat=1.5v) and two resistors with resistance r1=10ω and r2=5ω, connected in series with each other. what is the current running through the battery? (b) you re-arrange your circuit so now r2 is attached in parallel to r1 rather than in series. what is the current running through the battery? (c) you add an additional resistor r3=7ω on the same branch as r2. what is the current running through the battery? (d) what is the power dissipated in r3?

If you put a helium-filled balloon in the refrigerator, what will happen?