e202

E201: WORK, ENERGY AND POWER SERRANO, Jodel Christian R.

OBJECTIVE MATERIALS AND METHODS Materials Used in the Experiment:  One set Ballistic Pendulum with Accessories - It is used to determine the initial velocity of a bullet. This is the main material that was used.  One piece meter stick - It is used in determining the measurement of horizontal and vertical.  One piece carbon paper - It is used for determining the horizontal measurement in which it leaves a mark to measure distance.  One piece rod - It is used in pushing the bullet that is about to fire and to form a projectile motion. PART I. Determining the initial velocity of a steel ball using Ballistic Pendulum. 1. The mass of steel ball and Ballistic Pendulum is measured. 2. The Ballistic Pendulum has set in a balanced table. It was used in determining the velocity of the bullet. 3. The Pendulum bob’s height (between cross hair and table) using a ruler. Ruler was used in order to measure it easier than meter stick. 4. The steel ball was represented as the bullet. It was fired, then the displaced angle was recorded in order to get the vertical distance. The group had made fire trials to be more accurate in getting angle which was used in determining the final height. 5. The increase in height was computed by subtracting the computed final height and the measured initial height. After getting the height, the final velocity was computed with the use of conservation of mechanical energy equation, then the ball’s initial velocity (also called the firing

PART 1. 2. 3.

4. 5.

velocity) was also computed using conservation of momentum. II. Determining the Initial Velocity by Trajectory Method. The spring gun was set up in a table, and the Pendulum was raised upward in order for the ball to move freely or fire freely. Vertical distance (from floor-to-cross hair) of firing position was measured with the use if meter stick. The ball was fired first in order for the group to know where the carbon paper will locate. After that, the carbon paper will now be located, it is use to leave a mark where the ball lands. Ball is fired after it is done. The horizontal distance is recorded with the use of meter stick. Using the Kinematics Formula, the initial velocity has determined.

OBSERVATIONS AND RESULTS TABLE 1:Getting the Initial Velocity of the Steel Ball, Ballistic Method Mass of the steel ball,

m1 = 65.875 g

Mass of the Pendulum,

m2 = 245.8 g

TRIAL 1

Angle 27°

2

28°

3

29°

Initial height of the pendulum Final height of the pendulum Increase in height,

y 1=7.20 cm y 2=10.60 cm y=3.40 cm

y= y 2− y 1 4

27°

Velocity of the steel ball and the pendulum right after collision,

u=81.63 cm/s

u= √ 2 gy 5

27.5°

Average angle: 27.7°

Velocity of the pendulum before collision Velocity of the steel ball before collision,

v 2=0 cm/s v 1=386.23 cm/ s 1 | Page

m (¿ ¿ 1+m2) √ 2 gy m1 v 1=¿ Sample Computation: TABLE 2: Getting the Initial Velocity of the Steel Ball, Trajectory Method

v 1=x

2 Gravitational constant, g=980 cm/ s

TRIA L

Horizontal Distance,

x 1

158. 37 cm 2 156.07 cm 3 158.37 cm 4 158.37 cm 5 159.27 cm Average x: 158.09 cm

√

980 cm/ s2 v 1=(158.09 cm) 2(89.5 cm)

y=89.5 cm Height from the reference point to the ground

v 1=369.91 cm/s

Table 3: Velocity of the steel ball before collision,

v 1=369.91 cm/s

TABLE 3: Determining the Percentage Difference Percentage Difference, Percent difference = 4.32% (E V 1−E V 2)

diff =

v 1=x

√

g 2y

Sample Computations:  Velocity of the steel ball and the pendulum after collision

u= √ 2 gy

√

u= 2( 980

diff =

-------- Working equation

cm )(3.40 cm) s2

x 100

(386.23−369.91) x 100 386.23+369.91 2

diff =4.32 DISCUSSION & CONCLUSION

Velocity of steel ball before collision.

m ¿ 1+m (¿ 2) √ 2 gy m1 v 1=¿

E V 1+E V 2 2

Sample Computation:

u=81.63 cm/s 

√

g 2y

ACKNOWLEDGMENT & REFERENCE First of all, I would like to thank God for helping me to do this paper, for without Him, I would not gain knowledge and wisdom in working this.

---Working equation

v 1=

( 65.875 g) Also, Ig+245.8 acknowledge my 980professor, cm Mr. Ricardo de 2( )(3.40 cm) √ 2 Leon for his 65.875 g courage ins helping us in doing the

experiment. He helps us to understand the

v 1=386.23 cm/ s 2 | Page

experiment. He helps us to understand the given topic clearly which led us to a good result. Lastly, I thank my groupmates sharing one’s knowledge about and being excellent in doing without their help, we could not in the easiest possible way.

for cooperating, the experiment the experiment finish the paper

3 | Page