1)Vcm= m1v1+m2v2/(m1+m2)
vel of heavy block=14m/s vel of lighter block=0
so Vcm=14*5/(5+2)
=10m/s
(b)
2) vel of block 1 wrt com=14-10=4m/s
vel of block 2 wrt com=10-0=10m/s
diff in mag=10-4=6m/s
(a)
3) total kinetic energy=1/2 m1v1^2 + 1/2 m2v2^2
here v1 and v2 are vel wrt to com
so KE =100+40=140J
(c)