Question

question 7 (2 points)
mechanical energy (kinetic and potential) is always conserved.
true
false
question 8 (2 points)
gravitational potential energy can be thought of as the work done by gravity.
true
false
question 9 (2 points)
energy cannot be created nor destroyed, but only changed in form.
true
false

Explanation:

• For Question 7: Mechanical energy is conserved only in the absence of non - conservative forces like friction. So, it is not always conserved.
• For Question 8: Gravitational potential energy change is related to the negative of the work done by gravity. So the statement is false.
• For Question 9: This is the law of conservation of energy. Energy can only change forms.

Answer:

Question 7: B. False
Question 8: B. False
Question 9: A. True