An organ pipe open at both ends has two successive harmonics with frequencies of 210 hz and 240 hz. What is the length of the pipe? the speed of sound is 344 m/s in air.

Which two statements are true about a system? 1. a system is a group of objects analyzed as one unit. 2. energy that moves across system boundaries is conserved. 3. there’s only one way to define the boundaries of a system. 4. all systems are made by humans.

Which of these terms are associated with communication between neurons? chemical signals, electrical signals, synapse chemical signals, synapse, neurotransmitters synapse, electrical signals, chemical signals synapse, electrical signals, neurotransmitters

Feedback is given with little or no reservation 1.supportive 2.high-monitoring 3.positive 4.low-monitoring ?