Study Guide strand C test.

STUDY GUIDE for TEST STRAND C

1. One box is experiencing forces as follows: a 55N force pushing the box North, another force pushing North with a force of 15N; a force pushing South at 63N and another force pushing the box toward the South with a magnitude of 6 N. What is the 'net force' acting on this box?


2. Explain what happened when the astronauts did the experiment on the moon with the hammer and the feather.



3. An object has a mass of 3kg and experiences a force of 12 N. What would be this object's rate of acceleration?



4. A rat moved through a maze and covered .0004 miles in .05 hours. What was the average speed of the rat while it was moving in the maze?



5. Explain the law of electric charges.


6. Fully explain how a lightning rod works.


7. Provide an example of an electric discharge of static electricity.


8. What are the scientific names for the Northern and Southern lights, and what causes these to appear?

9. A bird flew from Jog road to the Turnpike, ( a distance of about 10,000 feet) and averaged a speed of 50 feet per second. How long did it take the bird to fly this distance?


10. Tony rode his pet mule to school. It took .4 hours and he averaged a speed of 3 miles per hour. What was the distance covered during this mule ride?


11. Brittany's pet bat, Brian escaped from its cage and eagerly flew to freedom. Brian increase his speed form 3m/s to 6m/s over the period of 3 seconds. What is Brian's acceleration rate?


12. Describe everything you know about a magnet and how it might interact with another magnet.


13. How do the GEOGRAPHIC pole locations of Earth compare with the MAGNETIC pole locations of Earth?

14. Explain Newton's 1st, 2nd, and 3rd laws of motion.



15. A ball is dropped from the top of a building. Describe what happens to that ball's rates of velocity and acceleration as it falls.


16. What is wave REFLECTION, REFRACTION and DIFFRACTION?


17. What is the difference between the different types of wave interferences?


18. What are the 6 simple machines discussed.



19. What is a 'compound machine' and give an example.


20. Why is a blackboard black and a whiteboard white, and a basketball orange?



21. What was demonstrated in class when the green laser beam was directed into a container of water?


22. We can see Jupiter (as well as several other planets) at night shining brightly. Why?


23. What is the difference between an object experiencing 'balanced forces' compared to 'unbalanced forces?'


24. What causes refraction of a light beam as it passes from one medium to another?


25. A ping from a submarine takes 36 seconds to go from the sub to the enemy ship and be heard once again back at the sub. If sound travels at about 1500 m/ s, then how far away is the enemy ship?


26. How does an object become charged by 'friction?'





ANSWERS to Study Guide

1. Total force pushing to the NORTH is 55 +15 = 70 N while total force pushing SOUTH is 63 +6 = 69 N. Total north force is larger by 1N, so net force is 1N North

2. When the hammer and the feather were dropped on to the surface of the moon, they both landed at the same time because there was NO ATMOSPHERE (in other words, it took place in the 'vacuum of space', and no air resistance.) When this experiment is done on Earth, the feather would fall SLOWER, and hit the ground AFTER the hammer - because the air resistance (friction) would have a much greater affect on the feather.

3. F=ma so a= f/m and 12N/3kg = 4m/s2


4. d=st so s=d/t and .0004miles/.05hr = .008miles/hr

5. It states that like charges will repel each other (a positive charge repels a positive and a negative repels a negative) while unlike charges are attracted to each other.

6. Because it is made of metal, it attracts lightning to it, and when it is struck, it channels the electricity into the ground via a wire (sometimes connected to metal water pipes) , thus 'grounding' the electricity. This provides some protection for the combustible materials which houses are made from.

7. Lightning, and when you get or give a shock after walking across a carpet.

8. Aurora Borealis and Aurora Australis are caused by the solar wind charged particles which collide with the Oxygen and Nitrogen in our outer magnetsphere. These collisions are much more noticeable at the magnetic poles, where the magnetic forces are strongest, and it causes the lights to appear.

9. d=st so t=d/s 10,000ft/50ft-second = 200 seconds = 3 minutes, 20 seconds

10. d=st so (.4 hr) ( 3mph) = 1.2 miles

11. a= the change in velocity / time = 6m/s -3m/s = 1 m/s
3 s

12. Magnets have a North and South Pole. Like poles repel, unlike poles attract. Earth behaves as if it has a huge magnet with a South magnetic pole near the North geographic pole and a North magnetic pole near the South geographic pole. A magnet has a magnetic field (with lines) surrounding it; areas with more lines have stronger force. A compass needle is a magnet which has a north pole (labeled N) that points to the geographic north pole. Electric current can cause a material to become magnetic. To be 'magnetic' requires the material's domains to be lined up in the same direction.

13. These poles are oppositely aligned (geographic north is near magnetic south pole.)

14. 1st- inertia (things at rest stay at rest, things in motion stay in motion-until acted on by an unbalanced force. 2nd- f=ma the acceleration of an object will depend on the size of the force exerted on it and also its mass. 3rd - forces exist in pairs, "for every action, there is an equal and opposite reaction."

15. As the ball drops, the velocity will increase faster and faster at a rate of increase known as acceleration. The velocity will reach a maximum 'terminal velocity' (top speed) in Earth's atmosphere due to air resistance. Once that top speed is reached, there is NO MORE INCREASE of speed, therefore no more acceleration (rate of acceleration then is= 0 )

16. Reflection is the BOUNCING of waves off an object such as light off a mirror, or sound off a canyon wall (echo); Refraction is the BENDING of waves as they pass from one medium to another; Diffraction is the bending of waves AROUND an OBSTACLE (sound does it well, while light not so well.)

17. Constructive is when the amplitudes of two waves add up to an amplitude larger than the initial waves; destructive is when the amplitudes of several waves combine to form a wave SMALLER than their original amplitudes.

18. Lever, wheel and axle (like a lever), inclined plane, wedge (like an inclined plane), screw (like an inclined plane), pulley

19. Two or more simple machines combined…. An apple corer.

20. Blackboard is black because ALL the colors of the rainbow (ROYGBIV) are absorbed into the blackboard…. Also why black clothes and cars get so hot! ; Whiteboard is white because it REFLECTS all of the colors of the rainbow (absorbs NONE)…….. the basketball is orange because the material absorbs all colors of the rainbow EXCEPT ORANGE which is the only color REFLECTED back to our eyes to see.

21. Reflection as the beam bounce up to the ceiling AND Refraction as the beam bent through the water.

22. Because of the REFLECTED white light of the SUN as it bounces off the planet.

23. Balanced forces result in a net force =0; unbalanced forces result in a net force NOT=0

24. The speed of the wave changes (slows down or speeds up)

25. One way trip would take 1/2 of the 36 seconds, or 18 seconds. If sound travels at 1500m/s , then over 18 seconds …. 18s x 1500 m/s = 27,000 meters away

26. By FRICTION, Electrons are wiped or rubbed from one object to a second object which then will have a negative charge. (note other ways to become charged are by direct contact -a simple touch: CONDUCTION; and indirect without contact: INDUCTION)