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Physics Exp. Procedures August 23, 2008

Filed under: Homeworks — seniorsass @ 8:29 pm
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typewritten version ni for printing purposes… au2 mu.. kamu na lang answer kai magka pareho nya tah… la pa pud ko answers… hehehe….

-SHERRY🙂

Central Force

Purpose: In this activity you will investigate situations involving central force.

Learning Station 1

Materials:

small plastic bag

marble or stone

a bigger stone twice as big as a marble or 5 washers

empty ballpen case

string 1½ m long

Procedure:

  1. Insert the string into the empty ballpen case.

  2. Wrap the marble or stone with a small plastic bag and tie it to one end of the string.

  3. Similarly, wrap the bigger stone (if washers are not available) and tie it to the other end of the string.

  4. The model should look like this:

  1. Whirl the object in a horizontal circle over your head at a constant rate.

    a. As the object is whirled, describe its speed and velocity.

  2. Make the horizontal circle bigger by increasing the length of the string.

a. What happens to the speed of the object?

b. What do you think is the function of the bigger stone that hangs at the other end of the string below the ballpen case?

c. Is there a force acting on the whirling stone? If there is, what is the direction of this force?

  1. Quickly cut the string just above or just below the ballpen case with a blade or knife as it is whirled.

a. Will the smaller stone still move in its circular path?

b. Make a sketch of the motion of this stone when the string is cut.

Learning Station 2

Materials: Comic strips given

Procedure:

  1. Read the given comic strips for about 5 minutes.

  2. Discuss and answer the following questions in your group:

    a. Sketch the path of a stone when the woman stands and throws a stone on a “smaller earth” like an asteroid.

    b. What provides the central force to the stone as it moves around the smaller earth?

    c. What enables satellites to travel around or orbit the earth?

Learning Station 3

Materials:

small pail (or a tall can of paint/milk with wire as handle

water

Procedure:

  1. Fill a pail halfway with water.

  2. Swing it in a vertical circle. Why does the water not spill?

Learning Station 4: The Sticky Coin

Materials:

wire coat hanger

25 centavo coin (or any other coin)

Procedure:

  1. Pull the middle of the longest straight length of the hanger out and shape it into a long narrow shape.

  2. Let the hanger hang on your right index finger (left, if you are left-handed) and place a coin on the end of the wire (sometimes this end needs to be filed, especially if it is not flat).

  3. Start to swing the hanger – first slowly back and forth, then do full loops (this needs a little practice) without dropping the coin.

  4. Swing it slower (when ending the swing) and try to catch the coin.

Questions:

  1. How could the coin stick against the end of the hanger?

  2. What kept the coin against the coat hanger?

  3. Would the coin still stick to the hanger if the swinging was done much slower?

  4. What applications in our daily life are similar to the whirling coin?

Apparent Weightlessness

Purpose: In this activity, you will observe the effects of gravity on objects in free fall.

Materials:

masking tape 2 styrofoam/paper cups

paper clip 2 rubber bands

water 2 washers/other objects of small mass

Procedure:

  1. Tie two rubber bands together to make one long rubber band. Then tie a washer to each end.

  2. Bore a small hole about the diameter of a pencil through the bottom of a styrofoam/paper cup.

  3. Fit the middle of the joined rubber bands through the hole from the inside of the cup. Use a paper clip to hold the rubber bands in place under the bottom of the cup.

  4. Let the washers hang over the lip of the cup such that the rubber bands are under some tension.

  5. Drop the cup from a height of 2 meters. What happens to the washers? Remove the rubber bands from the cup.

Outside the classroom:

  1. Use your finger as a stopper over the hole as you fill the cup half-full with water.

  2. Drop the cup from a height of 2m. What happens to the water as the cup falls?

  3. Repeat Steps 6 and 7 for a second cup half-filled with water with two holes bored through its sides.

Analysis:

a. Explain why the washers acted as they did in Step 5.

b. Explain why the water in the cup acted as it did in Steps 7 and 8.

 

One Response to “Physics Exp. Procedures”

  1. igotawayclean... Says:

    really appreciate it! …thanks!!


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