Unit 9

Question 1

Two people of the same mass climb the same flight of stairs. The first person climbs the stairs in 25 seconds and the second does this in 35 seconds. Which person does more work? Which person uses more power? Why?

Answer 1

-they do the same amount of work because work is
mass X distance and they are both the same
-the first person has more power because they do it in less time (work / time)

Question 2

Define potential energy (gravitational and elastic) and describe how to increase/decrease the potential energy of an object.

Answer 2

• potential energy is energy stored based on position (compression or height)
• in crease this by compressing a spring farther or increasing the height and decrease by doing the opposite.

Question 3

Define kinetic energy and describe how to increase/decrease the kinetic energy of an object.

Answer 3

• energy of an object due to its motion
• increase by the mass or velocity (velocity is squared so it will have a greater impact) and decrease by doing the opposite

Question 4

Describe the work energy theorum. Give an example.

Answer 4

• the amount of work done to an object is eaqual to the amount of change in kenetic energy
• moving a box across a floor

Question 5

Define mechanical energy and identify situations in which mechanical energy is conserved.

Answer 5

• the sum of Eg, Eel, and Ek

- at the top of a roller coaster there is all GPE but at the bottom there is all kenetic