4. The distance covered by a car at a time, t is given by x = 20t + 6t4 , calculate (i) the instantaneous velocity when t = 1 (4) (ii) the instantaneous acceleration when t = 1

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.

What you see with your eyes is a form of energy. a. light b. heat c. chemical d. electrical

Petroleum contains energy. a. light b. kinetic c. chemical d. mechanical