4.1 Video Motion Analysis using “Tracker”
TRIAL 1
(a) Displacement – time graph
(b) Velocity – time graph
(c) Acceleration – time graph
TRIAL 2
(a) Displacement – time graph
(b) Velocity – time graph
(c) Acceleration – time graph
Trial 3
a)Displacement-time graph
b)Velocity-time graph
(c)Acceleration-time graph
4.2 Data Analysis
1. Which wheels are your drive wheels?
Back wheels.
2. What is the circumference of your drive wheels?
30cm
3. How far will your car travel in one rotation of the drive wheel?
30 cm
4. How many rotations on average were there on each run?
20 rotations
5. How much string is needed on one rotation of the drive wheels?
String needed = Circumference of axle = 1.3cm
6. The release of the lever is the power stroke. What is the length of your vehicle's power stroke? (Length of string released)
33cm
7. Calculate how far your vehicle will travel during the power stroke. Show your calculations!!
Power Stroke = 33cm, One turn of wheel by string = 1.5cm
33/1.3cm = about 25.4 rounds (to 3 sf)
1 round of wheel = 30cm
30 x 25.4 rounds = 762cm
8. Compare the answer to #7 to the distance your measured during your car’s power stroke. Discuss possible reasons for different valuables.
Due to the smooth surface of the floor, the car may have skidded a little bit when travelling along the floor causing the distance to increase compared to what we calculated it would travel for as a distance.
9. Calculate the average velocity for your car during the period after the spring fully releases.
0.0935m/s
10. What force causes your car to stop?
Frictional Force.
11. The work done by a force is calculated by multiplying the force times the distance over which it acts. The work done on an object is equal to the change in its kinetic energy.Can you find a way to calculate the force of friction? Use equations and explain your steps. HINT: Be careful, you have average velocity.How can you find the total amount of kinetic energy (immediately after spring release) if we assume the acceleration during coasting was constant?
Values in the working below is the values during the part where the car was coasting (and answers are rounded off the 3 significant figures)
Average Speed of Car = 0.0935m/s (to 3sf)
In order to calculate the assumed kinetic energy of the car, in the case of no friction.
Let KEa be the assumed kinetic energy of the car
Let M = mass of the car = 300g = 0.300 kg
Let V = the average velocity of the car = 0.0935m/s
KEa = 1/2Mv^2
KEa=(1/2)(0.300)(0.0935)^2
= 0.00131J
In order to calculate the "force" applied to move the car,
Let F = the "applied force"
Let M = the mass of the car = 300g = 0.300kg
Let a = the acceleration of the car = 0.0001 m/s^2
F = M x a
F = (0.300) (0.0001)
F = 0.0003 N
In order to calculate the work done by the applied force,
Let Nd (and KEr) = the amount of work done in Joules by the applied force
Let N = the "applied force" = 0.0003N
Let m = the distance the car travelled = 0.6m
Nm = N x m
Nm = 0.0003 * 0.6
Nm = 0.00018 J
KEr = 0.00018 J
In order to calculate the work done by the frictional forces,
Let KEa = the assumed kinetic energy of the car
Let KEr = the amount of work done in Joules by the applied force
Let Fr = the amount of work done by friction (sound and heat)
KEa = KEr + Fr
Fr = KEa - KEr
Fr = 0.00131 - 0.00018
Fr = 0.00113J
In order to calculate the frictional force,
Let Nm (Fr) = the amount of work done by friction (sound and heat) = 0.00113J
Let N = the frictional force
Let m = the distance the car travelled = 0.6m
Nm = N x m
12. Various experiments have been done to measure the potential energy available from the spring. One estimate is 0.65 Joules. Using your estimates of the maximum kinetic energy of your car (lever) and the work done by friction, discuss whether or not this is a reasonable value. Can you account for any differences in the forms of energy? You must justify all of your arguments.
There were many different factors involved affecting the distance of the mousetrap car, that might have caused it to move further or shorter than what the potential energy provided by the spring of the mousetrap car would have allowed it to do. Hence, the estimate would not be accurate in calculating the amount of potential energy.
TRIAL 1
(a) Displacement – time graph
(c) Acceleration – time graph
TRIAL 2
(a) Displacement – time graph
(b) Velocity – time graph
(c) Acceleration – time graph
Trial 3
a)Displacement-time graph
b)Velocity-time graph
(c)Acceleration-time graph
1. Which wheels are your drive wheels?
Back wheels.
2. What is the circumference of your drive wheels?
30cm
3. How far will your car travel in one rotation of the drive wheel?
30 cm
4. How many rotations on average were there on each run?
20 rotations
5. How much string is needed on one rotation of the drive wheels?
String needed = Circumference of axle = 1.3cm
6. The release of the lever is the power stroke. What is the length of your vehicle's power stroke? (Length of string released)
33cm
7. Calculate how far your vehicle will travel during the power stroke. Show your calculations!!
Power Stroke = 33cm, One turn of wheel by string = 1.5cm
33/1.3cm = about 25.4 rounds (to 3 sf)
1 round of wheel = 30cm
30 x 25.4 rounds = 762cm
8. Compare the answer to #7 to the distance your measured during your car’s power stroke. Discuss possible reasons for different valuables.
Due to the smooth surface of the floor, the car may have skidded a little bit when travelling along the floor causing the distance to increase compared to what we calculated it would travel for as a distance.
9. Calculate the average velocity for your car during the period after the spring fully releases.
0.0935m/s
10. What force causes your car to stop?
Frictional Force.
11. The work done by a force is calculated by multiplying the force times the distance over which it acts. The work done on an object is equal to the change in its kinetic energy.Can you find a way to calculate the force of friction? Use equations and explain your steps. HINT: Be careful, you have average velocity.How can you find the total amount of kinetic energy (immediately after spring release) if we assume the acceleration during coasting was constant?
Values in the working below is the values during the part where the car was coasting (and answers are rounded off the 3 significant figures)
Average Speed of Car = 0.0935m/s (to 3sf)
In order to calculate the assumed kinetic energy of the car, in the case of no friction.
Let KEa be the assumed kinetic energy of the car
Let M = mass of the car = 300g = 0.300 kg
Let V = the average velocity of the car = 0.0935m/s
KEa = 1/2Mv^2
KEa=(1/2)(0.300)(0.0935)^2
= 0.00131J
In order to calculate the "force" applied to move the car,
Let F = the "applied force"
Let M = the mass of the car = 300g = 0.300kg
Let a = the acceleration of the car = 0.0001 m/s^2
F = M x a
F = (0.300) (0.0001)
F = 0.0003 N
In order to calculate the work done by the applied force,
Let Nd (and KEr) = the amount of work done in Joules by the applied force
Let N = the "applied force" = 0.0003N
Let m = the distance the car travelled = 0.6m
Nm = N x m
Nm = 0.0003 * 0.6
Nm = 0.00018 J
KEr = 0.00018 J
In order to calculate the work done by the frictional forces,
Let KEa = the assumed kinetic energy of the car
Let KEr = the amount of work done in Joules by the applied force
Let Fr = the amount of work done by friction (sound and heat)
KEa = KEr + Fr
Fr = KEa - KEr
Fr = 0.00131 - 0.00018
Fr = 0.00113J
In order to calculate the frictional force,
Let Nm (Fr) = the amount of work done by friction (sound and heat) = 0.00113J
Let N = the frictional force
Let m = the distance the car travelled = 0.6m
Nm = N x m
0.00113 = N x 0.6
N = 0.00113/0.6
N = 0.00188N12. Various experiments have been done to measure the potential energy available from the spring. One estimate is 0.65 Joules. Using your estimates of the maximum kinetic energy of your car (lever) and the work done by friction, discuss whether or not this is a reasonable value. Can you account for any differences in the forms of energy? You must justify all of your arguments.
There were many different factors involved affecting the distance of the mousetrap car, that might have caused it to move further or shorter than what the potential energy provided by the spring of the mousetrap car would have allowed it to do. Hence, the estimate would not be accurate in calculating the amount of potential energy.
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