Answer:We have , a relation in frequency f and wavelength λ of a wave having the velocity v as ,
v=fλ ,
given f=60Hz , λ=20m ,
therefore velocity of wave , v=60×20=1200m/s
Answer: The net force acting on the car 1,299.3 N.
Explanation:
Mass of the car = 710 kg
Initial velocity of the car of the ,u= 37 km/h= 10.27 m/s 
Final velocity of the car,v = 120 km/h = 33.33 m/s
time taken b y car = 12.6 sec
v-u=at





The net force acting on the car 1,299.3 N.