Apolice car traveling at a speed of 30.0 meters per second sounds its siren, which has a frequency of 1.00 × 103 hertz. as the police car approaches a stationary pedestrian, the pedestrian detects a siren frequency of

(a) assume the equation x = at^3 + bt describes the motion of a particular object, with x having the dimension of length and t having the dimension of time. determine the dimensions of the constants a and b. (use the following as necessary: l and t, where l is the unit of length and t is the unit of time.) (b) determine the dimensions of the derivative dx/dt = 3at^2 + b. (use the following as necessary: l and t, where l is the unit of length and t is the unit of time.)