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Kẻ mạnh không phải lúc nào cũng là kẻ chiến thắng. Kẻ chiến thắng mới chính là kẻ mạnh.
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Lab 1: Newton’s First law
Objective: The purpose of this experiment is to prove there is a relationship between Newton’s First Law and Momentum. There is no need for data or a specific procedure because this relationship is not measured, but can be observed.
Hypothesis: I believe that there is a relationship between inertia and momentum because every object has inertia and a momentum.
Materials:
• 2 Ballistics Cars (0.6559-kg) with bumper attatchment.
• 1 Metal Track
Procedure:
1. Set the metal track on a flat surface.
2. Lay two cars opposite of each other on the track, with the bumpers attatched to each.
3. Apply a force on one car, this will cause it to accelerate and hit the other car opposite of it, thus applying force on it.
4. Both cars have inertia. The car that has a non-zero momentum is the "outside force" which acts on the stationary ballistics car.
Data Results: No data is needed because the relationship between inertia and momentum is only an observable one, it is not measured.
Analysis: The force applied on one car causes it to accelerate towards the second car, when they collide they apply and impulsive force on each other, causing a change in momentum in both, the property of inertia is observed.
Conclusion: The magnitude of the momentum of the moving car equals the magnitude of the impulsive force it applied on the stationary car. The second car remained at rest until it was acted upon by the first, thus momentum can be related to inertia.
Lab 2: Newton’s Second Law
Objective: The purpose of this experiment is to prove there is a relationship between Newton’s Second Law and Momentum. We can prove this relationship by measuring the motion of the ballistics car.
Hypothesis: I believe that an applied force on the ballistics car will cause it to accelerate, this acceleration increases the car's velocity and therefore it's momentum, thus Newton's Second Law and Momentum are related.
Materials:
• 1 Ballistics Car (0.6559-kg)
• 1 Stopwatch
• 1 Meter Stick
• 1 Metal Track (1.225-m)
• 1 Accelerometer
• 1 Lab Interface
• 1 Calculator
Procedure:
1.Connect the Interface to its connected power source.
2. Plug in the accelorometer into port one of the interface.
3. Connect the interface to the computer.
4. Attach the accelorometer to the ballistics car, and place car on track with the rear wheels on the end of the track.
5. Measure the length of the track.
6. Open the program “Logger Pro 2.1” and open the file “Dual Force Sensors”.
7. Zero all sensors.
8. You will time the car as it traverses the track, the time stops when the rear wheels reach the opposite end.
9.Click Collect.
10. Apply a force on the ballistics car.
11. Click stop when the car reaches the end of the track.
12. Calculate the Car's final velocity by dividing the distance the car traveled by the time.
13. Calculate the Car's final momentum by multiplying the car's mass by it's final velocity.
13. Record all values on the data tables.
Data Results:
Mass of Car (kg) Force (N) Acceleration (m/s2)
0.6559 -2.46 -7.01
Vi (m/s) Vf (m/s) Pi (kg*m/s) Pf (kg*m/s)
0 0.586 0 0.384
Distance (m) Time (s)
1.225 2.09
Analysis: The Data shows that an applied force causes a change in momentum.
Conclusion: The -2.46 N force on the ballistics car caused it to accelerate, this acceleration increased the car's velocity by 0.586 m/s and this increase in velocity caused a change in momentum of 0.384 kg*m/s. This data proves the relationship between Newton's Second Law and Momentum.
Lab 3: Newton’s Third Law
Objective: The purpose of this experiment is to prove there is a relationship between Newton’s Third Law and Momentum. We can prove this relationship by measuring the motion of a ballistics car, before and after it's impact with a stationary box.
Hypothesis: I believe that the ballistics car and the box will apply equal and opposite forces on each other when they collide, this will cause a change in momentum of the ballistics car.
Materials:
• 1 Force Sensor
• 1 Ballistics Car (0.6559-kg) with bumper attatchment
• 1 Stopwatch
• 1 Metal Track (1.225-m)
• 1 Accelerometer
• 1 Calculator
• Tape
• 1 Box
Procedure:
1.Connect the Interface to its connected power source.
2. Plug in the accelorometer into port one of the interface.
3. Connect the interface to the computer.
4. Attach the accelorometer to the ballistics car, and place car on track with the rear wheels on the end of the track.
5. Measure the length of the track.
6. Open the program “Logger Pro 2.1” and open the file “Dual Force Sensors”.
7. Zero all sensors.
8. You will time the car as it traverses the track, and you will time the contact between the box and car.
9.Click Collect.
10. Apply a force on the ballistics car using the force sensor itself, hit the pushing attatchment of the sensor against the back of the car.
11. Click stop when the car stops moving.
12. Because impulse and change in momentum are equal, you can calculate the magnitude of these by multiplying the applied force by the duration of the contact between the box and the car.
13. Record all values on the data tables.
Data Results:
Acceleration Before Collision (m/s2) Acceleration After Collision (m/s2)
0.196 0.184
Mass of Car (kg) Force (N) Time of Contact(sec.)
0.6559 3.89 0.14
Analysis: The ballistics car and the box applied equal and opposite forces on each other when they collided, this caused a change in momentum of the ballistics car.
Conclusion: An applied force caused a car to accelerate toward a stationary box. The box and car applied equal but opposite forces on each other when they collided. This force can be called an impulsive one because it was applied for a certain time on both objects. This impulsive force causes a change in acceleration on the balllistics car, this change of acceleration causes a change in the car's velocity and therefor a change in its momentum. This proves that there is a correlation between Newton's third law of equal and opposite forces and momentum.
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