3/20 Physics update and homework due 3/27

Hi folks,

Today we got a bit deeper into our energy study by taking a look at the concepts of work and power.


To get some experience with the concept of work we we used a spring scale to find out how much force it took to move a wooden block a certain distance over several different surfaces. The students then multiplied the force times the distance to see what work was done.

We also found out how much work it took to get the students to go up a flight of stairs. Then, using that information we timed the class as they ran up the stairs and used that to find their power.

For homework this week do the following questions:


1. What does it mean if something is doing work on something else in Physics?




2. If someone was trying to push on a wall and the wall didn't move, are they doing work on the wall?





3. If someone was doing pushups are they doing work on themselves? Are they doing work on the floor? Why or why not?






4. If someone told you they exerted 500 J of energy on a box, would you have any idea how long it took them to do the work? What unit that we studied in class this week would tell you how long it took to do the work?






5. What two things did you need to measure to find out how much work you did on the block?






6. What three things did you need to measure to find out how much power you had when you were climbing the stairs?