Can someone answer questions 2 - 7 for me ?

Question No.2

speed= distance/ time  

1200km/0.006s= 200 000 km/s 

Question 4

wavelength = wavespeed / frequency 

wavespeed = 16/8 = 2 

Question 5

(400/60s) = 6.6667 waves/ sec (Hz). 
Velocity = 0.008m/sec. 
Wavelength = (v/f) = 0.008/6.6667 = 0.0012 metre (1.2mm).

Well if you have 20 bats you probably want 20 balls? you don’t have enough context to answer the question.