6. What is fuel needed for in space? 7. Could a rocket traveling at a speed of
10,000 km/h get into space? Explain.
8. Why is thrust also known as the
reaction force?
9. Why does a rocket not need to burn
fuel to keep moving once it is in space?

Two loudspeakers, 5.5 m apart and facing each other, play identical sounds of the same frequency. you stand halfway between them, where there is a maximum of sound intensity. moving from this point toward one of the speakers, you encounter a minimum of sound intensity when you have moved 0.33 m . assume the speed of sound is 340 m/s. part a) what is the frequency of the sound? part b) if the frequency is then increased while you remain 0.21 m from the center, what is the first frequency for which that location will be a maximum of sound intensity? express your answer to two significant figures and include the appropriate units.