How does the Doppler effect explain why a siren's pitch increases as it approaches you? A. The siren moves away from sound waves it has already produced, increasing their wavelength.
B. The siren moves closer to sound waves it has already produced) decreasing their wavelength
C. The siren moves away from sound waves it has already produced decreasing their wavelength,
D. The siren moves closer to sound waves it has already produced, increasing their wavelength

An athlete swings a ball, connected to the end of a chain, in a horizontal circle. the athlete is able to rotate the ball at the rate of 8.13 rev/s when the length of the chain is 0.600 m. when he increases the length to 0.900 m, he is able to rotate the ball only 6.04 rev/s. (a) which rate of rotation gives the greater speed for the ball? 6.04 rev/s 8.13 rev/s (b) what is the centripetal acceleration of the ball at 8.13 rev/s? m/s2 (c) what is the centripetal acceleration at 6.04 rev/s? m/s2