The Doppler effect can be used to measure flow rates in blood. A sound wave is transmitted into a vein or an artery, where it is reflected off the moving red blood cells and then detected by a receiver. A transmitter uses a frequency of 11.2 MHz, and the blood flow rate is 0.55 m/s. What is the expected frequency shift? (Take the speed of sound in blood to be 1524 m/s. Assume the blood is moving directly toward the transmitter.) Answer in kHZ.