From left:CHAN CHING HUI BK07110266, YEOH CEH HSING BK07110212, LEE SIN HAO BK07110228, MOHD IZHA BIN MD YUSOP HK20062283, JASON LIEW FOOK MIN BK07110132, LIM SHING YEU BK07110271, KOAY QING SHENG BK07110355, WONG SIN YONG BK07110230
Intro to our group members
From left:CHAN CHING HUI BK07110266, YEOH CEH HSING BK07110212, LEE SIN HAO BK07110228, MOHD IZHA BIN MD YUSOP HK20062283, JASON LIEW FOOK MIN BK07110132, LIM SHING YEU BK07110271, KOAY QING SHENG BK07110355, WONG SIN YONG BK07110230
Finally Our Group Experiment Has Been Carried Out
After discussing with group members of our experiment of projectile motion, we decided to carry out our experiment on 26 March 2009 after our class.
We have prepared out our experiment apparatus and done the experiment at the outside of Robotcon Lab. Four members had been come for the experiment who is Lim Shing Yeu, Wong Sin Yong, Lee Sin Hao and Yeoh Ceh Hsing. We separeted the work load for each other. Shing Yeu and Sin Hao responsible for setting up the apparatus and lauched the apparatus. On the other hands, Ceh Hsing and Sin Yong responsible for note down the results. A few of assumptions have been made for the experiment.
After 1 hour later, we sucess to get the result that we want which related to projectile motion and energy conservation. Then, the results was saved and brought back for analysing and further discussing with group members.
Finally, we have taken the photos which related to the experiments that we have done. The photos will be posted through this blogs soon.
Created by Yeoh Ceh Hsing
We have prepared out our experiment apparatus and done the experiment at the outside of Robotcon Lab. Four members had been come for the experiment who is Lim Shing Yeu, Wong Sin Yong, Lee Sin Hao and Yeoh Ceh Hsing. We separeted the work load for each other. Shing Yeu and Sin Hao responsible for setting up the apparatus and lauched the apparatus. On the other hands, Ceh Hsing and Sin Yong responsible for note down the results. A few of assumptions have been made for the experiment.
After 1 hour later, we sucess to get the result that we want which related to projectile motion and energy conservation. Then, the results was saved and brought back for analysing and further discussing with group members.
Finally, we have taken the photos which related to the experiments that we have done. The photos will be posted through this blogs soon.
Created by Yeoh Ceh Hsing
Drafting and brainstorming for idea
During our first meeting, all of the members gathered at sktm foyer. A few idea had been suggested and then every aspect of the ideas were disscussed. This is to ensure that the idea can be realise and suitable for apply. From those idea, one was choosed which is combination of kinetic energy and projectile motion. Many problems were identified and dicussion was carried out to find the solution. All the members were asked to research for the neccessary details of the experiment and discuss again during next meeting. The meeting was postponed until next meeting.
At the next meeting, with the collected details, Qing Sheng was in charge with doing the proposal. A copy of proposal was submitted to Mr Chua Bih Lii upon completion.
Done by: Koay Qing Sheng
At the next meeting, with the collected details, Qing Sheng was in charge with doing the proposal. A copy of proposal was submitted to Mr Chua Bih Lii upon completion.
Done by: Koay Qing Sheng
What Mean The Projectile Motion
A projectile is an object upon which the only force acting is gravity. There are a variety of examples of projectiles. An object dropped from rest is a projectile (provided that the influence of air resistance is negligible). An object which is thrown vertically upward is also a projectile (provided that the influence of air resistance is negligible). And an object is which thrown upward at an angle to the horizontal is also a projectile (provided that the influence of air resistance is negligible). A projectile is any object which once projected or dropped continues in motion by its own inertia and is influenced only by the downward force of gravity
By definition, a projectile has only one force acting upon it - the force of gravity. If there was any other force acting upon an object, then that object would not be a projectile. Thus, the free-body diagram of a projectile would show a single force acting downwards and labeled force of gravity (or simply Fgrav). Regardless of whether a projectile is moving downwards, upwards, upwards and rightwards, or downwards and leftwards, the free-body diagram of the projectile is still as depicted in the diagram at the right. By definition, a projectile is any object upon which the only force is gravity.
The concept of projectile motion is difficult to understand as that the only force acting upon an upward moving projectile is gravity. Their conception of motion prompts them to think that if an object is moving upward, then there must be an upward force. And if an object is moving upward and rightward, there must be both an upward and rightward force. Their belief is that forces cause motion; and if there is an upward motion then there must be an upward force. They reason, "How in the world can an object be moving upward if the only force acting upon it is gravity?" Such students do not believe in Newtonian physics (or at least do not believe strongly in Newtonian physics). Newton's laws suggest that forces are only required to cause an acceleration (not a motion). Recall from the Unit 2 that Newton's laws stood in direct opposition to the common misconception that a force is required to keep an object in motion. This idea is simply not true! A force is not required to keep an object in motion. A force is only required to maintain an acceleration. And in the case of a projectile that is moving upward, there is a downward force and a downward acceleration. That is, the object is moving upward and slowing down.
To further ponder this concept of the downward force and a downward acceleration for a projectile, consider a cannonball shot horizontally from a very high cliff at a high speed. And suppose for a moment that the gravity switch could be turned off such that the cannonball would travel in the absence of gravity? What would the motion of such a cannonball be like? How could its motion be described? According to Newton's first law of motion, such a cannonball would continue in motion in a straight line at constant speed. If not acted upon by an unbalanced force, "an object in motion will ...". This is Newton's law of inertia.
Suppose that the gravity switch is turned on and that the cannonball is projected horizontally from the top of the same cliff. What effect will gravity have upon the motion of the cannonball? Will gravity affect the cannonball's horizontal motion? Will the cannonball travel a greater (or shorter) horizontal distance due to the influence of gravity? The answer to both of these questions is "No!" Gravity will act downwards upon the cannonball to affect its vertical motion. Gravity causes a vertical acceleration. The ball will drop vertically below its otherwise straight-line, inertial path. Gravity is the downward force upon a projectile which influences its vertical motion and causes the parabolic trajectory which is characteristic of projectiles.
A projectile is an object upon which the only force is gravity. Gravity acts to influence the vertical motion of the projectile, thus causing a vertical acceleration. The horizontal motion of the projectile is the result of the tendency of any object in motion to remain in motion at constant velocity. Due to the absence of horizontal forces, a projectile remains in motion with a constant horizontal velocity. Horizontal forces are not required to keep a projectile moving horizontally. The only force acting upon a projectile is gravity!
- Created by Yeoh Ceh Hsing
By definition, a projectile has only one force acting upon it - the force of gravity. If there was any other force acting upon an object, then that object would not be a projectile. Thus, the free-body diagram of a projectile would show a single force acting downwards and labeled force of gravity (or simply Fgrav). Regardless of whether a projectile is moving downwards, upwards, upwards and rightwards, or downwards and leftwards, the free-body diagram of the projectile is still as depicted in the diagram at the right. By definition, a projectile is any object upon which the only force is gravity.
The concept of projectile motion is difficult to understand as that the only force acting upon an upward moving projectile is gravity. Their conception of motion prompts them to think that if an object is moving upward, then there must be an upward force. And if an object is moving upward and rightward, there must be both an upward and rightward force. Their belief is that forces cause motion; and if there is an upward motion then there must be an upward force. They reason, "How in the world can an object be moving upward if the only force acting upon it is gravity?" Such students do not believe in Newtonian physics (or at least do not believe strongly in Newtonian physics). Newton's laws suggest that forces are only required to cause an acceleration (not a motion). Recall from the Unit 2 that Newton's laws stood in direct opposition to the common misconception that a force is required to keep an object in motion. This idea is simply not true! A force is not required to keep an object in motion. A force is only required to maintain an acceleration. And in the case of a projectile that is moving upward, there is a downward force and a downward acceleration. That is, the object is moving upward and slowing down.
To further ponder this concept of the downward force and a downward acceleration for a projectile, consider a cannonball shot horizontally from a very high cliff at a high speed. And suppose for a moment that the gravity switch could be turned off such that the cannonball would travel in the absence of gravity? What would the motion of such a cannonball be like? How could its motion be described? According to Newton's first law of motion, such a cannonball would continue in motion in a straight line at constant speed. If not acted upon by an unbalanced force, "an object in motion will ...". This is Newton's law of inertia.
Suppose that the gravity switch is turned on and that the cannonball is projected horizontally from the top of the same cliff. What effect will gravity have upon the motion of the cannonball? Will gravity affect the cannonball's horizontal motion? Will the cannonball travel a greater (or shorter) horizontal distance due to the influence of gravity? The answer to both of these questions is "No!" Gravity will act downwards upon the cannonball to affect its vertical motion. Gravity causes a vertical acceleration. The ball will drop vertically below its otherwise straight-line, inertial path. Gravity is the downward force upon a projectile which influences its vertical motion and causes the parabolic trajectory which is characteristic of projectiles.
A projectile is an object upon which the only force is gravity. Gravity acts to influence the vertical motion of the projectile, thus causing a vertical acceleration. The horizontal motion of the projectile is the result of the tendency of any object in motion to remain in motion at constant velocity. Due to the absence of horizontal forces, a projectile remains in motion with a constant horizontal velocity. Horizontal forces are not required to keep a projectile moving horizontally. The only force acting upon a projectile is gravity!
- Created by Yeoh Ceh Hsing
Theory Behind The Projectile Motion
Theory:
Projectile Motion
Following the prescription, the trajectory for projectile motion is derive by eliminating t from the equations for the horizontal and vertical component of the projectile motion:
We get the following formula:
Here Ox is the launch angle, ie
As we had mentioned previously the trajectory for projectile motion is parabolic. There are a few useful expressions which can be derived from this equation. The maximum range on level ground is the distance between y=0 solutions:
We see that this expression is maximal for
Another interesting characteristic of projectile motion is the max height. To determine it we need only consider the motion in the y-direction. The following equation holds for this motion with constant acceleration:
Remember that these formulae only hold for projectile motion on flat ground. For more complicated cases you will have to work the formulae for r(t) and the trajectory yourself so make sure you understand what went on in these derivations.
Created by Yeoh Ceh Hsing
Projectile Motion
Following the prescription, the trajectory for projectile motion is derive by eliminating t from the equations for the horizontal and vertical component of the projectile motion:
x = v0x t
y = v0x t
We get the following formula:
y = tan Ox – [g x2 / 2 (v0 cos Oo)2]
Here Ox is the launch angle, ie
tan Oo = voy / vox
As we had mentioned previously the trajectory for projectile motion is parabolic. There are a few useful expressions which can be derived from this equation. The maximum range on level ground is the distance between y=0 solutions:
R = vo2 sin 2O / g
We see that this expression is maximal for
Oo= 45 degree where the range is
Rmax = v02 / g
Note that the smaller g the larger range, so we can throw almost 10 times further on the moon than on earth! Also note that the range decreases for steeper as well as for shallower angles which means that for any range less than max-range there are two elevations which will mach. Highest elevation always keeps the projectile in air longer so if we want to get there fast we use the lower elevation.Another interesting characteristic of projectile motion is the max height. To determine it we need only consider the motion in the y-direction. The following equation holds for this motion with constant acceleration:
vy2 = v0y2 – 2ghmax
At maximum height we havevy= 0. We insert this value in the equation and solve for h to get
h max = V0y2 / 2g
Remember that these formulae only hold for projectile motion on flat ground. For more complicated cases you will have to work the formulae for r(t) and the trajectory yourself so make sure you understand what went on in these derivations.
Created by Yeoh Ceh Hsing
Introduction To Our Experiment
The law of conservation of energy states that the total amount of energy in an isolated system remains constant. A consequence of this law is that energy cannot be created or destroyed. The only thing that can happen with energy in an isolated system is that it can change form which is to say for instance kinetic energy can become thermal energy or elastic energy can become kinetic energy. From the Einstein's theory of relativity (E = mc²), energy is associated with mass in, that’s mean the conservation of energy also implies the conservation of mass in isolated systems. This state means that the mass of a system cannot change, so long as energy is not permitted to enter or leave the system.
Figure: Measuring Tape
The objective for this project is to prove the conservation of energy. Before this project will be made, there are a few assumption need to be made; the air resistant ignored, conversion of energy is ideal, the acceleration of gravity is constant and the spring is frictionless. A ball bearing will be launch by the Ball Bearing Spring Launcher at a certain height. The ball will travel some distance and fall back to ground due to gravity acceleration. The motion of the ball bearing will be resolve into horizontal component, x and vertical component, y. The distance travel by the ball will be measured by the measuring tape. Calculation will be done base on each component. The time taken by the ball to fall back to the ground will be recorded using a stopwatch. These results can be used to find the velocity of x component which will not be affected by acceleration of gravity. Then the initial projectile velocity can be determined. After that, the initial velocity is used to find the kinetic energy and the distance the spring has been compressed away from the equilibrium position is used to find the elastic potential energy of spring. Finally, the theory of conservation of energy between the elastic potential energy of spring and the kinetic energy of the ball bearing is proved.
Posted by Mohd Izha Bin Md Yusop
Figure: Ball Bearing Spring Launcher
Figure: Measuring Tape
The objective for this project is to prove the conservation of energy. Before this project will be made, there are a few assumption need to be made; the air resistant ignored, conversion of energy is ideal, the acceleration of gravity is constant and the spring is frictionless. A ball bearing will be launch by the Ball Bearing Spring Launcher at a certain height. The ball will travel some distance and fall back to ground due to gravity acceleration. The motion of the ball bearing will be resolve into horizontal component, x and vertical component, y. The distance travel by the ball will be measured by the measuring tape. Calculation will be done base on each component. The time taken by the ball to fall back to the ground will be recorded using a stopwatch. These results can be used to find the velocity of x component which will not be affected by acceleration of gravity. Then the initial projectile velocity can be determined. After that, the initial velocity is used to find the kinetic energy and the distance the spring has been compressed away from the equilibrium position is used to find the elastic potential energy of spring. Finally, the theory of conservation of energy between the elastic potential energy of spring and the kinetic energy of the ball bearing is proved.
Posted by Mohd Izha Bin Md Yusop
Abstract
In this project, the main purpose is to prove the theory of conservation of energy. By using a spring system and projectile motion, the theory of energy will be proved. The spring device will launch a ball bearing in a horizontal direction at a certain height from ground. The ball will having semi-projectile motion. The projectile motion of a ball bearing will be observed. From the theory, the energy due to a spring will be the same as the energy exerted by a ball bearing that having a motion. The theory of projectile motion will be use in order to find the initial velocity. The distance travel by a ball bearing will be measure to the find initial velocity of the ball, the relation between the velocity and distance travel. The velocity achieved will be used in the equation of kinetic energy. The comparison will be made in the Result & Analysis Section.
Posted by Mohd Izha Bin Md Yusop
Posted by Mohd Izha Bin Md Yusop
Objective
There are 2 objectives in this experiment.
1. To study the properties of projectile motion
2. To show and prove the conservation of energy
Posted by Mohd Izha Bin Md Yusop
1. To study the properties of projectile motion
2. To show and prove the conservation of energy
Posted by Mohd Izha Bin Md Yusop
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