HOMEWORK-- WAVES

ON A BLOCK PAGE, DO NOT COPY THE PROBLEMS, SHOW ALL YOUR PROCESS!!

1. Logan, Cassie and Abbey are doing the Pulse Speed Lab. Logan and Cassie stand 6.8 m apart and stretch a zinc-coiled snakey between them. Logan introduces a pulse into the snakey at his end. Using a stopwatch, Abbey measures that it takes 15.1 seconds for the pulse to travel to Cassie's end and back two times. They then repeat the experiment with a copper-coiled snakey stretched the same distance and find that pulses travel back and forth two times in 16.9 seconds.
a. Determine the speed of the pulse in the zinc-coiled snakey.
b. Determine the speed of the pulse in the copper-coiled snakey.

2. A transverse wave is observed to be moving along a lengthy rope. Adjacent crests are positioned 2.4 m apart. Exactly six crests are observed to move past a given point along the medium in 9.1 seconds. Determine the wavelength, frequency and speed of these waves.

3. A marine weather station detects waves which are 9.28 meters long and 1.65 meters high and travel a distance of 50.0 meters in 21.8 seconds. Determine the speed and the frequency of these wave.

Problems done outside to finish for Homework

These are the problems you need to finish if you didn't in class.

1. Cathy, a 460 N actress playing Peter Pan, is hoisted above stage in order to “fly” by a stagehand pulling with a force of 60 N on a rope wrapped around a pulley system. What is the Mechanical Advantage of the pulley system?

2. A windmill uses sails blown by the wind to turn an axle that allows a grindstone to grind corn into

meal with a force of 90 N. The windmill has sailsof radius 6.0 m blown by a wind that exerts a force

of 15 N on the sails, and the acle of the grindstone has a radius of 0.50 m.

a)What is the Ideal Mechanical Advantage of the wheel?

b)What is the actual Mechanical Advantage of the wheel?

c)What is the efficiency of the wheel?

3. Mr. Macintoch, a computer technician, uses a screwdriver with a handle of radius 1.2 cm to remove a screw in the back of a computer. The screw moves out 0.20 cm to each complete turn. What is the Ideal Mechanical Advantage of the screwdriver?

4. A nutcracker 16 cm long is used to crack open a Brazil nut that is placed 12 cm from where your hand is squeezing the nutcraker. What is the Ideal Mechanical Advantage of the nutcracker?

Potential Energy-- activity's problems

Here are the problems you were supposed to finish in class. Make sure to finish them.

a)    *Legend has it that Isaac Newton “discovered” gravity when an apple fell from a tree and hit him on the head. If a 0.20 kg apple fell 7.0 m before hitting Newton, what was its change in PE during the fall?

b)    *It is said that Galileo dropped objects off the Leaning Tower of Pisa to determine whether heavy or light objects fall faster. If Galileo had dropped a 5.0 kg cannon ball to the ground form a height of 12 m, what would have been the change in PE of the cannon ball?

c)    *A 0.80 kg bird, perched on a power line 6.0 m above the ground, swoops down to snatch a worm form the ground and then returns to an 8.0 m high tree branch with his catch. By how much did the bird’s PE increase in its trip from the power line to the tree branch?

d)    *A Mexican jumping bean jumps with the aid of a small worm that lives inside the bean. If a bean of mass 2.0 g jumps 2.5 cm from your hand into the air, how much potential energy has it gained in reaching its highest point?

FOR GEOGRAPHY 7TH GRADE STUDENTS!!!!!

These are the instructions you need to follow to earn the 10 bonus points. Make sure to follow them correctly!

Use the map given to you, or print the one above, to do the following:

•Use a red color to outline the United States.

•Use a blue color to outline Canada.

•Put a Yellow star where the Capital City of each country is. Label the Capital Cities.

•Write the name of 20 of the states in the United States.

•Write the name of the 10 provinces and 3 terrotories in Canada.

•Write the names of the oceans these countries border with.

•Identify and label the 3 largest cities in US with an orange dot.

•Identify the capital city of 5 provinces in Canada with a black dot.

•Write, next of each country, the year of its independence.

Elastic and Inelastic Collisions.- Homework due on Monday, February 14th

This homework must be handed-in on block paper before 8:00 am on the due date. Problems must be copied and all process must be shown. The final answer must be in a red rectangle. Any instruction not will cause a lower grade.

1. Miguel, the 72.0 kg bullfighter, runs toward an angry bull at a speed of 4.00 m/s. The 550 kg bull charges toward Miguel at 12.0 m/s and miguel must jump on the bull's back at the last minute to avoid being runover.
a) What kind of collision is this?
b) What is the new velocity of Miguel and the bull as the move across the arena?

2. Charlotte, a 65.0 kg skin diver, shoots a 2.0 kg spear with a speed fo 15 m/s at a fish who darts quickly away without getting hit. How fats does Charlotte move backwards when the spear is shot?

3.Jeanne rolls a 7.0 kg bowling ball down the alley for the league championship. One pin is still standing, and Jeanne hits it head-on with a velocity of 9.0 m/s. The 2.0 kg pin acquires a forward velocity of 14.0 m/s.
a) What kind of collision is this?
b) What is the new velocity of the ball?

4. To test the strength of a retainment wall designed to protect a nuclear reactor, a jet aircraft was crashed head-on into a concrete barrier at high speed. The jet aircraft had a mas of 19100 kg, while the retainment wall's mass was 469000 kig. The wall sat on a cushion of air that allowed it to move during impact. If the wall and the aircraft moved together at 8.41 m/s during the collision,
a) what was the initial speed of the aircraft?
b) What kind of collision is this?

5. A 620.0 kg moose stands in the middle of the railroad tracks, frozen by the lights of an oncoming 10000 kg locomotive that is traveling at 10.0 m/s. The engineer sees  the moose but is unable to stop the train in time and the moose rides down the track sitting on the cowcatcher.
a) What kind of collision is this?
b) What is the new combined velocity of the locomotive and the moose?

MOMENTUM.- Homework due Wednesday February 9, 2011 (for 8th A and 8th C only)

Solve the following problems on your notebook. Copy the problems and show all your process, hand in your notebook before 8:00 am.

1.    On April 15,1912, the Luxury cruiseliner Titanic sank after running into an iceberg. What momentum would the 4.23 x 10⁸ kg ship have imparted the iceberg if it had hit the iceberg head-on with a speed of 11.6 m/s?

2.    Auto companies frequently test the safety of automobiles by putting them through crash tests to observe the integrity of the passenger compartment. If a 1000 kg car is sent toward a cement wall with a speed of 14 m/s and the impact brings it to a stop in 0.08 s, with what average force is it bought to rest?

3.    Rhonda, who has a mass of 60.0 kg, is riding at 25 m/s in her sports car when she must suddenly slam on the brakes to avoid hitting a dog crossing the road. She is wearing a seatbelt, which brings her body to stop in 0.400 s,

a)    What average force did the seatbelt exert on her?

b)    If she had not been wearing her seatbelt, and the windshield had stopped her head in 0.001 s, what average force would the windshield have exerted on her?

OCTOBER SKY-- Questions for 8th A

As you can see, because of their situation, nobody believed the "Rocket Boys" could accomplish anything, even their parents. That could happen to you, but if you believe in yourself, and even if it looks as the most difficult thing to do (like Rocket science!!), you can do it. You can accomplish anything you want if you put your very best effort. And you will always find a teacher to believe in you and to support you in everything  =).
You can copy them into Word, answer themn and print them out, or you can answer them in a block page. Hand them in tomorrow before 8:00 am

1.  What is the name of the Town where the story takes place?

2.  What event happens that makes the boys, especially Homer, become interested in rockets?

3.  Who’s the first person to believe in them and to help them?

4.  Why are they put in jail?

5.  Why did Homer quit his dream and went to work at the mine?

6.  What was Homer’s brother good at?

7.  Why did not all of the boys go to the Science Fair?

8.  What happens at the Science Fair that made them almost lose the competition? Who helps them to overcome that?

9.  Out of the four boys, who did not get to go to college?

10.              Who did Homer dedicated his last launch at the place?