The appropriate label for the slope of this graph is

km/hr
km/hr/s
km/s
km/m
the appropriate label for the slope of this graph is

km/hr
km/hr/s
km/s
km/m

both go with the pic!

The appropiate label for the slope in this graph is km/hr/s

km/hr/s

This graph show about the acceleration for the moving obeject that the acceleration is constant,  (it is always the same acceleration 6 km/h/s). 

acceleration =velocity/time
To compute acceleration we need two points:
(10,60)
(0,0)

aceleration=(60-0)km/h/(10-0)s)=6 km/h/s

Mass is the amount of matter in an object.  weight is the measurement of the pull of gravity on an object.  say for example, you travel to the moon which has a different gravitational field compared to the gravitational field of earth. (gravitational fields: earth = 1, moon = 0.165)  now when you are on the moon, the pull of gravity on you is different than on the earth. and as weight is the measurement of the pull of gravity on an object, that means yes, your weight can and will change on the moon.  however, on the moon, on earth or even on jupiter, the amount of mass inside of you remains the same. meaning your physical mass remains constant.  in conclusion it is possible for your weight to change as your mass remains constant.