The next step I will take is to exam closer the work of Sir Isaac Newton as it bears some relevance to my work:
Law 1. Any object will continue what it is already doing unless a resultant force is acting on it.
Newton’s first law states that the net force on an object is proportional to the acceleration that object undergoes. If there is no net force, by Newton’s first law, there can be no acceleration. A book on a table experiences a downward force due to gravity, and an upward force due to the table pushing on the book (called the normal force). The two forces cancel each other out exactly; there is no net force, so the book does not accelerate off the table.
This idea that an object on the ground, which is given energy to start it moving, will come to rest quickly. Of course once it is moving friction is a force that will act against it. Friction is a force that acts upon an object , on the floor, in this case a reduction in velocity, until the object stops. Without friction, as in space, an object given a push will continue in a straight line with the velocity it had when initially pushed.
Law 2. Constant acceleration causes constant acceleration. The greater the force, the greater the acceleration for that particular body.
Newton's second law relates net force and acceleration. A net force on an object will accelerate it—that is, change Its velocity. The acceleration will be proportional to the magnitude of the force and in the same direction as the force. The proportionality constant is the mass, m, of the object
F = ma
Acceleration, a, is measured in m/s2. Mass is measured in kg; force, F, in Newtons. A Newton is defined as the force necessary to impart to a mass of 1 kg an acceleration of 1 m/s2; this force is roughly equal to the weight of a 100g object at sea level.
A more massive object will require a greater force for a given acceleration than a less massive one.
Law 3. When an object is acted on by a force then somewhere another object is acted on by an equal force in the opposite direction.
Newton's third law of motion states that when an object exerts a force on another object, it experiences a force in return. The force that object one exerts on object two must be of the same magnitude as the force that object two exerts on object one but in the opposite direction. On a skating rink, for example, if a large adult gently pushes away a child, then in addition to the force the adult exerts on the child, the child exerts an equal but oppositely directed force on the adult. Because the mass of the adult is larger, however, the acceleration of the adult will be smaller.
Newton's third law also requires the conservation of momentum, the product of mass and velocity. For an isolated system, with no external forces acting on it, the momentum must remain constant. In the example of the adult and child on the skating rink, their initial velocities are zero, and thus the initial momentum of the system is zero. During the interaction, internal forces are at work between adult and child, but net external forces equal zero. Therefore, the momentum of the system must remain zero. After the adult has pushed the child away, the product of the large mass and small velocity of the adult must equal the product of the small mass and large velocity of the child. The momenta are equal in magnitude but opposite in direction, thus adding up to zero.
Apparatus: Margerine tub
Plastercine
Newton Meter
Stool
2 Rubber Bands
Metre Ruler
Chalk/Floor Marker
Stopwatch
Power Pack
Ticker Timer
Ticker Timer Tape
Weighing Scales
Method:
• Collect apparatus
• Place margarine tub and plastercine on weighing scales and record result.
• Link the two rubber bands together, like so:
• Put the two ends of the combined rubber bands underneath the legs of the stool, like so:
• With a Newton Meter pull the rubber band under the stool and every Newton the rubber band is being pulled mark on the floor where each Newton pulls the rubber band. Pull from the middle of the two rubber bands on the join so that it is approximately in the middle. You should get around ten Newtons marked on the floor depending on the strength and the amount of ‘stretch’ the rubber band has.
• Mark on the floor in front of the stool every 10cm or so to give you rough range of how far the margarine tub will travel.
• Place your weighed margarine tub with plastercine on the floor in front of the rubber band and pull back on the rubber band so that the back of the margarine tub is on the 1N mark and then release and simultaneously you must start the stopwatch and stop as soon as the margarine tub stops. Record your results. You can either measured from the front of the margarine tub or the back, but once you have chosen one you must continue measuring from the same place on the margarine tub each time.
• Repeat the above step for each Newton mark on the floor
• Record your results in a table as the one below:
• You will need to show an example of the acceleration. Set-up the power pack connect the ticker timer to the power pack.
• Pass the ticker tape through the timer and connect it to the margarine tub
• Start the ticker timer and release the margarine tub.
Variables: In this experiment the variables are the weight of the margarine tub, it is crucial that the same equipment is used if the experiment goes on for longer than one lesson. It is important because we want our results to bear a pattern. If we change the tub, the velocity of the tub maybe different because there will be a different amount of friction created and the aerodynamics will be different. If we change the rubber bands, the results will change according to the tension of the rubber bands. We must also take it to account the floor surface. For example, we conducted our experiment on the corridor where it is tiled, the tiles are smooth but it some places uneven. This may affect my results. Also others conduct there experiments in the classroom where the is rough but even. These factors may effect our results. The only variable that will change is the force exerted to move the margarine tub (measured in Newtons (N)).
Diagram:
Safety: On the surface this is not a highly dangerous experiment, however what must be shown is the awareness of the environment around us. There may be more than one group maybe working in a small area. Therefore everyone should be vigilant.
Results:
Conclusion: I believe my results are not very accurate. After the experiment the is one more objective that I need to achieve that is to investigate the F=MA rule and so I have made a table baring the relevant information to work this formula.
To get as accurate results as possible I ensured that each time I conducted the experiment I used the same equipment, for example, I used the example same rubber bands for the catapult, the same margarine tub, the same amount of plastercine to way the tub down and also the same floor surface which was a smooth tiled corridor. My only variable was the force needed to move the margarine tub. Each time I catapulted the margarine tub I increased the force exerted from the catapult by one Newton until the rubber band is extended to its full potential of ten Newtons. I must also consider how precise I want my results. I believe that two decimals should be sufficient.
Evaluation: My results were not very accurate. I know this because in the table above, if my knowledge serves me correctly, Mm/s2=N, if so the Actual Force column should be the same as the Newtons column, of which it is not. But as the two columns are or such vast differences I am led to believe that the mentioned equation is untrue and I am unsure of what F may represents. It maybe just that I have miscalculated, or maybe my response times in stopping or starting the stopwatch was too slow I don’t know. If I had more time it would be wise to re-conduct the experiment. Maybe then the stopwatch being replace with laser beams as we have used them before I think it would be very accurate for timing the margarine tub with. Also because the results are not accurate I cannot establish a link between acceleration, force and mass and how they affect each other. So therefore I feel I have failed what I set out to do.
