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Physics: Work, Power, Energy Essay

Power and Energy Earlier Bambino, Jeanne Marie Bernard, Petersen Cleric Camion, Asia Case Department of Biological Sciences College of Science, University of Santos Atoms Spans, Manila Philippines Abstract The experiment deals primarily with computing the work done by gravity on each member in two scenarios (going up and down the stairs of the second floor and the third floor of the Main Building) wherein weight was also considered and following this, the power output of each member was also computed.

Using the Logger Pro, the kinetic and potential energies of a ball in free fall were graphed and compared. At the end of the experiment, it was said that member #2 was the most “powerful” among the group since she had the highest power output both in going up and going down the stairs and in the second activity, the results were obtained and the predictions made were correct. 1. Introduction Work, power and energy are three words that are commonly used in a man’s activity involving a force and movement in the direction of the force. Energy is the ability to do work.

Power is the rate of doing work or the rate of using energy. This experiment was designed to demonstrate the conservation of canonical energy, to measure change in kinetic and potential energies as a ball moves in free fall and to determine power output when going up and down the stairs. 2. Theory This experiment is to studying work, power and energy. The following equations are used for certain unknowns in activity one. F stands for force. Mass (m) of the individual is multiplied to gravity (g). Gravity is equal to 9. 8 m/so. W=FDA W stands for work.

F is for force solved from the previous equation and d stands for the distance traveled. P stands for power. Work is divided to time (t) to obtain the value of power. When a force acts upon an object to cause a displacement of the object, it is said that work was done upon the object. There are three key ingredients to work – force, displacement, and cause. In order for a force to qualify as having done work on an object, there must be a displacement and the force must cause the displacement. The standard metric unit of power is the Watt.

As is implied by the equation for power, a unit of power is equivalent to a unit of work divided by a unit of time. Thus, a Watt is equivalent to a Joule/second. For historical reasons, the horsepower is occasionally used to describe the power delivered by a machine. One horsepower is equivalent to approximately 750 Watts. In terms of Energy wherein we used the Logger Pro to graph, three graphs were obtained. These were potential energy, kinetic energy and total mechanical energy. Potential energy is the stored energy of position possessed by an object. Kinetic energy is the energy of motion.

An object that has motion – whether it is vertical or horizontal motion – has kinetic energy. In the process of doing work, the object that is doing the work exchanges energy with the object upon which the work is done. When the work is done upon the object, that object gains energy. The energy acquired by the objects upon which work is done is known as mechanical energy. Mechanical energy is the energy that is possessed by an object due to its motion or due to its position. Mechanical energy can be either kinetic energy (energy of motion) reportorial energy (stored energy of position).

Objects have mechanical energy if they are in motion and/or if they are at some position relative to a zero potential energy position. 3. Methodology The materials used to perform this experiment are rubber ball, timer, meter stick ND Logger Pro. Fig. 1. 1 A graphical interpretation off person going up the stairs. Fig 1. 2 Interpretation on how to get vertical distance of stairs Activity 1 (Power) started with determining the weight of each group member. Then the members demonstrated going up the stairs of the third floor and fourth floor of the Main Building while being timed.

The time it took for the members to go down the stairs from the third floor to the fourth floor was also noted. Next, the members had to devise a way to determine the vertical distance (h) between the third floor and each step was noted and added altogether. Next, the work done by gravity on each member when going up and down the stairs was computed as well. Lastly, the power output of each group member was computed as well and the most “powerful” member of the group was determined. Activity 2 ( Energy of a Tossed Ball: Physics with Computers) weighing the rubber ball that was to be used.

Then, the members predicted the graphs for the potential energy versus time off ball thrown vertically up from a height of 50 CM. , graph of kinetic energy versus time of the same ball, graph of total mechanical energy versus time of the same ball. The members then placed the motion detector protected with a wire basket on the floor. The file “16 Energy of Tossed Ball” was opened and a member held the ball directly above and 50. 0 CM from the motion detector while another member tossed the ball straight up while the motion detector began to collect data.

The graphs obtained using Logger Pro were then compared to the predicted graphs. 4. Results and Discussion Table 1: Activity 1 (Power) vertical distance between second floor and third floor: 5. 021 m Member 1 Bernard 1 occasion 1 cacaos I weight (N) | 421. 4 N | 529. 2 N | 470. 4 N I work going up 0) 1 2115. J 12457. 11 J 12361. 88] I Time to go up(s) 1 13. As 1 11. As | 16. 8 s I power output in going 162. IOW 1 223. IOW 1 140. IOW I work in going down 0) 1 2115. 85] | 2657. 11] | 2361. 88] | DomesticationГџ) 19. As | 11. 1 s 112. As I power output in going down (W)1 215. IOW 1 239. OWE 1 193. IOW I A person is also a machine that has a power rating. Some people are more power- full than others. That is, some people are capable of doing the same amount of work in less time or more work in the same amount of time. A common physics lab involves quickly climbing a flight of stairs and using mass, height and time information to determine a student’s personal power. Despite the diagonal motion along the staircase, it is often assumed that the horizontal motion is constant and all the force from the steps is used to elevate the student upward at a constant speed.

Thus, the weight of the student is equal to the force that does the work on the student and the height of the staircase is the upward displacement. Activity 2 (Energy of a Tossed Ball: Physics with Computers) Fig 2. 1 : Potential energy vs.. Time Fig 2. 2 Kinetic energy vs.. Time ball weight: 74. 47 g. The motion of a dropped ball can be examined using a motion detector. As the ball falls to the ground, it speeds up until it strikes the ground. At that point, it reverses direction and bounces off the ground and back into the air.

In addition to examining the position and velocity of the ball as it falls and bounces back, the total mechanical energy (ME) of the ball can be found. ME is the sum of the kinetic and gravitational potential energies of the ball. The ball has gravitational potential energy (PEE) if it is some vertical height above a predetermined reference point; the greater the distance, the greater the gravitational potential energy. The ball has kinetic energy EKE) if it has a non-zero velocity; the greater the velocity, the greater the kinetic energy. The mass of the ball also plays a role.

For example, these factors can easily be observed by dropping different mass balls from the same height onto sand. All the balls will have the same velocity before hitting the ground. But, the more mass a ball has, the more work it can do on the sand and the greater the divot (hole) the ball can make. Putting all of this together, the various energies can be expressed as follows: Upgrade = MGM and EKE = h move. There are other types of energy to consider, which we will not directly measure. These include the elastic gravitational potential energy Plastic of the ball.

When the ball strikes the ground, it compresses like a spring, and the kinetic energy is converted to elastic potential energy. If there are no external forces acting on the ball (like friction, air resistance, etc. ), then ME is conserved. 5. Conclusion In this experiment, the work done by gravity on each member when going up and down the stairs was computed and the weight of each member was also noted since weight is a factor that would affect the result. From this, the most “powerful” group member was determined. For the second part of the experiment, the members predicted the graphs for the potential energy vs.. Mime, kinetic energy vs.. Time and total mechanical energy vs.. Time and used the Logger Pro to check if the predicted graphs were correct in comparison to the obtained results. From this, the group members found out that if there are no external forces acting on the ball (like friction, air resistance, etc. ), then ME (Mechanical Energy) is conserved. 6. Applications a) According to Physics, when you are climbing stairs the force of gravity is attracting you towards earth due to which you need to apply more force than gravity to go upstairs.

While coming downstairs you have to apply less energy because you are already moving in the direction of force which is coming from gravity that’s why its harder to climb stairs while easy to come downstairs b) Yes Power is the rate of doing work. It takes exactly the same amount of work to raise the professor from the first floor to the third whether he takes it in one long flight of stairs or two shorter flights of stairs. Enough power to raise itself through one flight of stairs at an acceptable pace and hen needs a period of rest to remove combustion products and renew energy supplies before assailing the second set of stairs.

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