If you know the answer just answer it please :) Which is an example of gravitational potential energy only.

Question 2 options:

a puppy walking around under a tree

a rolling skateboard going down a hill

an apple resting on the teacher’s desk

an elevator moving up to the 3rd floor

Answer asap need by wednesday morning explain how a buffer works, using an ethanoic acid/sodium ethanoate system including how the system resists changes in ph upon addition of a small amount of base and upon addition of a small amount of acid respectively. include the following calculations in your i. calculate the ph of a solution made by mixing 25cm3 0.1m ch3cooh and 40cm3 0.1m ch3coo-na+. [ka = 1.74 x 10-5 m] ii. calculate the ph following the addition of a 10cm3 portion of 0.08 m naoh to 500cm3 of this buffer solution. iii. calculate the ph following the addition of a 10cm3 portion of 0.08 m hcl to 200cm3 of the original buffer solution.

The velocity of any object depends upon a) the location of the object. b) the location of the observer. c) which measurement tools are used. d) the relative motion of the observer.

Just on number 2 (all parts), and if you do answer explain in detail