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Expirement 5:Newton's Law 2

Deep Panjwani

September 14, 2011

Burhan Riaz

Andrew Im

Jessica Danaux

Anthony Pesare

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Objective:

Experiment 1: To investigate the forces acting on an object on an incline and predict and

observe the object's acceleration.

Experiment 1: To investigate the forces acting on the masses in an Atwood's machine and

predict and observe the masses' acceleration.

Equipment:

Data studio file "g sin theta.ds" - this program was used to record data the velocity of thecart. An additional graph compared the acceleration to the height of the starting point of

the cart.

Data studio file "18 Atwood's Machine" - records the velocity that created by the twodifferent weights on the smart pulley.

Ramp - Used to accelerate the cart. Photogates: - Measures the velocity of the cart. Cart - The object being measured. Smart Pully - is rotated by the string and measures velocity. Weights - used to create velocity on the smart pulley.

Mass Hangers - attaches the different weights together.

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Procedure:

Experiment 1:

1. Put the 5-pattern picket slots on the top of the cart so that the row with 1cm bands are ontop. Attach the photogates with mounting brackets on the bottom of the track. Plug the

photogate into Digital Channel 1 of the PACO interface.

2. Use the ring stand and clamp to raise on end of the track to create an incline.3. Open the file "g sin theta.ds."4. For each trial, measure the height of the track and use the height and length to calculate

the sin theta. Raise the track and record the acceleration and analyze the information.

Experiment 2:

1. The smart pulley should be mounted at the edge of the table.2. Use a piece of string about 10cm longer than the distance from the top of the pulley to

the floor. Place the sting in the groove of the pulley.

3. Attach a mass hanger to each end of the string. Put 60g on the hanger and 50g on theother. Record the total mass on both sides.

4. Open the file "18 Atwood's Machine." Use DataStudio to record the velocity vs. time.Use this graph to extract the acceleration of the masses and record.

5. Move one gram from the heavier to the lighter weight. Repeat the measurement andrecord your data. Repeat 5 times.

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Data Analysis:

Sin theta vs. Acceleration(m/ss)

The trend you can see here shows that as sin theta increases, the acceleration also increases.

Experiment 1 Data Table

Sin theta Acceleration(m/ss)

Trial 1 4.8 0.3

Trial 2 7.8 0.9

Trial 3 9.3 1

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Trial 4 12.8 1.4

Trial 5 15.7 2.1

Trial 6 22.2 3.2

Velocity of Weights vs. Time

What we see here is that as the difference of weights get higher, the higher the acceleration.

Weight1(g)

Weight2(g) Acceleration(m/ss)

TheoreticalAcceleration(m/ss)

PercentDifference(%)

Trial 1 56.6 66.6 0.78 0.8 2.5

Trial 2 57.6 65.6 0.58 0.64 4.8

Trial 3 58.6 64.6 0.4 0.48 18.2

Trial 4 59.6 63.6 0.26 0.32 20.7

Trial 5 60.6 62.6 0.13 0.16 20.7

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Experiment #1 questions:

1. We predicted that as the sin theta increases, the acceleration of the cart should alsoincrease. From the graph, you can see that our predictions were correct.

2. The plot's y-intercept should be 0 because at 0 sin theta the cart is not moving. The slopeshould be positive because acceleration should increase as sin theta increases. Our data

shows that y-intercept is slightly negative (graph not shown) and that the slope is .104.

3. We can find acceleration by looking at the slope of the velocity vs. time graph due to theproperties of acceleration and velocity. To find g, we use the equation

g=(acceleration/sin theta). G should be 9.8. One our data points showed that g was 8.5.

Experiment # 2 questions:

1. We extracted the acceleration by using the slope of the velocity of weights vs. timegraph.

2. (See data table) a=(M-m)g/(M+m).3. (See data table) The trend is that as the acceleration increases, the percent difference

increases. I think this happens because the theoretical acceleration does not take into

account the friction caused by the string and the pulley. Also air resistance is not taken

into account.

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Conclusion:

Experiment 1: What we learned from this experiment is the relationship of the incline in the

equation a=(g)(sin theta). We now know that as sin theta increases, a also increases.

Experiment 2: In this experiment, we found that the relationship between two weights tied by the

same string on a pulley is represented by a=(M-m)g/(M+m). So as the difference between the

weights increase, the acceleration increases.