Answer:
I think it's 3) speed and direction
The time must be measured with respect to gravity. As it falls, it has free fall that is the force acting on it will be the gravity.With the distance in account, d = 1/2 gt²
t = √(2d/g)
The motor does 20 J of work on the block, it means that the total mechanical energy of the block has increased by 20 J. But the increase in total mechanical energy is equal to the sum of the increases in potential energy and kinetic energy:

So, if the gravitational potential energy has increased by 15 J, the kinetic energy has increased by
The force of gravity is the
force with which massively large objects such as the earth attracts another
object towards itself. All objects of the earth exert a gravity that is
directed towards the center of the earth. Therefore, the force of gravity of
the earth is equal to the mass of the object times acceleration due to gravity.
F = ma
4.9N = m (9.8 m/s^2), note that
N (newtons) = kg-m/s^2
<u>m = 0.5 kg</u>
<u>The mass of the object is
0.5kg.</u>