Understanding Force and Mass in Kangaroo Jumps

[danield]

Hey.. i am having problems solving the following question...

2) A 40-kg kangaroo exerts a constant force on the ground in the firs 60 cm of her jump, and rises 2.0 m higher. When she carries a baby kangaroo in her pouch, she cna rise only 1.8 m higher, What is the mass of the baby kangaroo?

I am not interested in the answer so much.. but in the logic of the problems.. i just can't do a free body diagram for them..
please help
,dan

 

[radou]

Well, for (1), which forces are acting on the crate? Further on, what does the constant velocity tell you about the forces acting on the body?

 

[danield]

ok 1.. i could solve.. i used the equation of force applied+weight=force of friction, and i found force applied and the direction.
But I am still having trouble wiht 2)

 

[danield]

Well I've been trying to do something like 2y/g=t^2, then V=y/t and then A=v/t, but i guess that is not working, i think I've been seeing it from the wrong angle, but any way i try i can't get the answer :(