a = -Ve/Me × dM/dt
dM/dt = Mi/120 ÷ 1sec = -Mi/120sec
a =-2400/Mi ( -Mi/120) = 20m/s²
PS: This is the textbook solving but, I don't know how dM= Mi/120
I am OKWUCHI Peter Joseph and I'm a citizen of Nigeria. I look forward to gaining knowledge and also contribute immensely to the growth of the community.