How much work is required to push a 2.0-kg object up a frictionless inclines plane whose length is 2.0m and whose height is 1.0m, if the velocity of the object remains constant?

20 Joules.

Explanation:

As , the incline is frictionless , only work done to push a block up the incline is only due to the gravitation resisting the upward movement .

Also, gravitational work only depends upon the height upto which the block is taken .

W = mgh .

Here, mass m of the object = 2.0 kg

g = 10m/

h = 1.0 m

Thus, W = 2×10×1 = 20 Joules.

So, 20 Joules of work is required to push an object of 2.0 kg mass up the frictionless incline .

t = 1/400 h   ⇔ 0.0025 h ⇔ 9s ⇔ 0.15 m

any of the answers are correct.