Determine the maximum (instantaneous) acoustic power produced by a lecturer speaking loudly from the podium (80 dB SPL). Describe your assumptions about the directivity of this sound source.

A1200 kg car traveling north at 10 m/s is rear-ended by a 2000 kg truck traveling at 30 m/s. what is the total momentum before and after the collision?

Your target variable is δf, the magnitude of the difference in frequency between the waves emitted from the sonar device and the waves received by the device after reflecting off the whale. write an expression for δf in terms of the relevant frequencies using the subscript notation introduced above.

Anybody wanna ? (picture included? )