Review for Week 21 DCA
1. What is the formula for density? Mass/volume
2. What instruments do you use to measure density? Triple beam balance and graduated cylinder
3. List which step of the scientific method is being used: PROBLEM, HYPOTHESIS, PROCEDURE, DATA, CONCLUSION
a. __Conclusion__ Based upon several observations colored light had no effect upon my dog’s feeding habits.
b. __Hypothesis _My dog will eat better under red light.
c. __Problem____ Does my dog eat better when exposed to a particular color of light?
d. __Procedure_____ Observe the dog’s feeding habits for 7 days, using a colored light each time.
e. __Data___My dog ate his entire meal each of the seven days in just under 3 minutes.
4. What is potential energy? Stored energy
What is kinetic energy? Energy of motion
Draw a roller coaster showing different levels with loops and label
the potential and kinetic energy. Where is the most potential energy? Where is
the most kinetic energy?
Look on the board!
5. What is happening in this picture?
à ß
_One arrow is bigger than the other so the forces are unequal
_The arrows are pointing in opposite directions so the forces are acting in opposite directions.
_The bigger arrow has a larger force
Which direction would the box move? Why?
The box would move to the left because there is a larger force acting on it.
6. What is formula for speed?
Distance/time
7. If you go a distance of 50 meters in 10 seconds, what is your speed?
50m = 5m/s
10 s
8. What is the average speed if you have gone a total distance of 160 meters in 10 seconds?
160m =16m/s
10 s
9. How do you figure out average speed on a data table? You add all the speeds together and divide by the total number to get the average. Ex. 90m/s +90m/s +90m/s= 270/3= 90m/s for the average speed.
10. How do you figure out average speed on a graph?
You look at the last data point for distance and divide that by the total number of seconds. Ex. A man walked and the last point plotted on his walk was 20meters divide that by the total number of seconds he walked (5 seconds) and you get 20m/5s=4m/s for the average speed
11. Give an example of an inclined plane?
A ramp, a staircase
12. What does diameter mean?
the length of a straight line through the center of an object from side to side; width; thickness; as, the diameter of a tree or rock
13. On a graph, if you see a line steadily going up, would a person be moving at a constant speed? ___yes____ Please draw what this would look like.
14. On a graph, if someone is taking a break and not moving, what does this look like? Draw.
______
15. On a graph, if someone is reversing directions and coming back to a reference point what does this look like? Draw.
16. Draw 2 inclined planes, one as a short steep ramp and one as a longer ramp with the same “steepness”. Tell which one would use less force to push a sofa up the ramp.
A shorter steeper ramp uses more force so to use less force you should use a longer ramp to push the sofa up the ramp.
17. Do simple machines like pulleys and inclined planes make our lives easier? Yes
18. What is a fixed pulley? A Fixed pulley is a pulley that is attached to a structure and does not move, but changes the direction of the effort force used to lift a load by a person. Examples: Cranes, flag, sail on boat, curtain rod, mini-blinds.
19. What is a movable pulley? A pulley that moves with the load. The movable pulley allows the effort to be less than the weight of the load so you use less effort to pull the load.
20. Do you need more or less pulleys to make the load easier? More
21. Draw a picture of a fixed pulley carrying a box and label the load and input force, and show arrows showing the direction of force on both the pulley and the box.