Answer: D.) 39,200 J
Via the equation of potential energy PE = mgh where m is mass, g is the average gravity on earth and h is the height. In this case m = 400 kg, g = 9.8, h = 10 m thus:

P.E.= 39,200 Joules
Answer: See photo
Explanation: There are a couple of ways to use velocity in an equation in the photo.
The density of the object is approximately 1.91 kg per m³.
42 kg is a measure of mass, and 22 m³ is a measure of volume. Knowing this, you can use the relationship

to solve for the object's density.
42 kg

22 m³

1.91 kg per m³.
Yes the plot dose make it with out baking out