NEWTONS SECOND LAW OF MOTIONActivity #10I. Objectives:To study newtons second law of motion and its application.

II. Abstract: The laws of mechanics are embodied in the general principles of law of motion d stated and formulated by Isaac Newton. Newton's second law of motion pertains to the behaviour of objects for which all existing forces arenotbalanced. The second law states that the acceleration of an object is dependent upon two variables - thenet forceacting upon the object and the mass of the object. The acceleration of an object depends directly upon the net force acting upon the object, and inversely upon the mass of the object. As the force acting upon an object is increased, the acceleration of the object is increased. As the mass of an object is increased, the acceleration of the object is decreased.Consider two masses connected by a light flexible cord passing over a light frictionless pulley. Since the masses are equal, the system is in equilibrium, that is, it will remain at rest or if given a slight impulse, will move with a uniform speed without acceleration. If a small body is added, the system will move with an acceleration a

III. Schematic DiagramFigure I Balance BeamFigure II Strings

Figure III Meter StickFigure IV Set of Weights

Figure V Iron StandFigure VI Pulley

Figure VII Light Pans

Figure VIII Actual Set Up

IV. Data TableData ResultsTrial 1Trial 2Trial 3

Average time, t (s)

0.650.610.67

M1 (g)

250250250

M2 (g)

100100100

Distance, s (cm)858585

Value of a from eq. 1(cm/s2)402.37456.87378.7

Value of a from eq. 2420420420

PERCENT DIFFERENCE4.4 %8.1 %10.1 %

V. SAMPLE COMPUTATIONTrial 1:Trial 2: Trial 3:S= at2S= at2S= at285cm= a(0.65s)285cm= a(0.61s)285cm= a(0.67s)2a= 402.37 cm/s2a= 456.87 cm/s2a= 387.7 cm/s2% E= eq. 1- eq. 2/ eq.1 x 100 % E= eq. 1- eq. 2/ eq.1 x 100 % E= eq. 1- eq. 2/ eq.1 x 100%E = 4.4%%E = 8.1 %%E = 10.1%

Theoretical: For Trial 1, 2 and 3:Equation 2: (m1 + m2)g/ m1+m2 = (250g-100g)(980cm/s2) 250g+100g= 480cm/s2

VI. Conclusion

From the data that was taken during this investigation we can see that this graph shows accelerations that change constantly at the same rate. Throughout this experiment the hanging mass (force) is increased which reduces the amount of air resistance it faces, thus making the acceleration faster, but still constant with the other accelerations. We learned that our prediction at the start of this experiment was proven to be correct. We hypothesized that as the mass on the hanger increases, the air resistance, will decrease, thus the acceleration of the object towards the center of the earth would be increased. The relationship between the acceleration and mass is proportional. It shows that the acceleration is directly proportional to the mass. This experiment proved our point, but many possible errors were overlooked.

VII. Question/Analysis

1. A 325-g weight is acted upon by a constant force which changes its speed from 1.20 m/s to 0.4 m/s in1.20 s. Find the accelerating force.

2. A mass of 800 g rests on a smooth horizontal plane. It is tied to a string which passes over a frictionless pulley at the end of the plane. At the free and of the plane. At the free end of the string a, mass of 250-g is hung. How far will the smaller mass move in 3 sec. starting from rest? What is the tension in the string?

3. A man of mass m is standing on a scale in an elevator. If the elevator, originally going down at uniform speed, slows down, what would become of the reading on the scale? Support your answer with a free body diagram of the scale.

4. In the experiment, if friction were present between the shaft and pulley, will the system have a greater or lesser acceleration then when it has no friction?

VIII. Recommendation

Throughout the experiment we have not considered the force of friction. Even though this experiment has not included friction, it was present in between the carts wheels and along the surface of the track. Even though it is treated as frictionless, friction is always present everywhere, even if it is regarded as not present. Another force that we excluded was air resistance. During the experiment the window in the classroom was open and wind was blowing, changing the air resistance in the room. Even though the change in air resistance might be minor, it is still another source of error that can lead to miscalculation. The last source of error we overlooked is that the car was not always placed in the exact same place on the track. Since it was not placed on the same spot every time, the friction and air resistance was not always exactly the same but still close enough to prove Newtons Second Law.Throughout the experiment, we proved our hypothesis right, and we scouted, and avoided all the avoidable sources of error to the best of our abilities.

IX. Referenceshttp://www.google.com.ph/?gfe_rd=cr&ei=RNniVNboKsaJ8QeepoDoAg#q=newton%27s+second+law+of+motionhttp://www.physicsclassroom.com/class/newtlaws/Lesson-3/Newton-s-Second-Lawhttp://schoolworkhelper.net/newton%E2%80%99s-second-law-lab-answers/