The question is a fairly straight-forward examination of kinematics from HSC Physics Module 5.
There is no data given, hence your answer must be qualitative, not quantitative.
For 3 marks, you need to state three good, solid facts about the motion of both objects.
The energy changes you could mention are:
(a) loss of gravitational potential energy, both objects fall through the same vertical height.
(b) both objects gain the same amount of kinetic energy, in the vertical direction.
(c) decompose the motion of m1 into horizontal and vertical components of velocity. Object m1 has constant horizontal component of velocity, but accelerated vertical velocity.
(d) object m1 has greater impact velocity than object m2, due to initial horizontal component of velocity.
(e) no loss of kinetic energy from atmospheric friction (because there is no atmosphere)
If you combine all that into seven lines, you would get full marks.