a$)$ A mass M$1=20$ kg is suspended by a light string from the ceiling

of a lift of mass M$2=400$ kg$.$

i$)$ If the lift accelerates upwards at $1\mathrm{.}5$ m$/$s$2,$ what is the tension

in the lift cable and in the string? $[3$ marks$]$

ii$)$ If the string breaks when subjected to a tension of more than

$600$ N$,$ what is the greatest possible tension in the lift cable

so that the string remains intact? $[3$ marks$]$