12-Oct-2016: Ballistic Pendulum

Lab: Ballistic Pendulum
Name: Andrew Martinez
Lab Partners: Richard Mendoza, Lynel Ornedo

Statement: To determine the firing speed of a ball in the spring-loaded experiment

Introduction: In this lab we will be for three things. The firing speed of the ball and to determine the trajectory the ball will travel and its landing point. Using our knowledge of potential energies, conservation of momentum, and conservation of energy we can determine all three.

Procedure:
Part 1
- Measure the length of the string holding the block in place
- Measure the height of the table
- Record the masses of the ball and block
- Place the ball into the spring-loaded gun and select which level to set it at
- Place the angle indicator at zero
- Fire the ball into the block and record the max angle
- Repeat five times
- Use the conservation of momentum to write an equation to find the speed of the system after the collision

Part 2
- Use the value gained in part one after the collision
- Use conservation of energy to and relate the max height to the initial speed of the block
- Using these value predict where the ball well land if launch from table height then find actual

Apparatus:

Ballistic Pendulum with the scale to measure mass

Measured Data
Mass_ball: 7.6 g +/- .1 g
Mass_block: 79.2 g +/- .1 g
Tables height: 85.8 cm +/- .01 cm
String length: 20 cm +/- .01 cm
Trail Angles: 17 degrees, 15 degrees, 16.5 degrees, 17 degrees, 14.5 degrees
Average Angle: (17+15+16.5+17+14.5)/5 = 16 degrees

Calculated work

Vf of mass (ball+block) = .3897 m/s
Vi of mass ball = 4.45 m/s
T = .436 s
X = 1.94 m (experimental)
X = 2.02 m (Actual)

Analysis:
Setting kinetic energy = to gravitational potential energy we get an equation which can be rearrange to solve for Vf = .3897 m/s. Using the value of Vf we relate the height to initial velocity and solve for Vi getting 4.45 m/s. We then use kinematic equations for the x-axis to find how far the ball will travel before impact and use a kinematic for the known height to find time. We get 1.94 m as the estimate range of impact. Upon actually launching we found the true impact point to be 2.02 m.

Conclusion:
This lab demonstrates how by using the laws of conservation of momentum and energy as well potential energies one can determine unknown velocities and predict there range. These estimations are reasonable accurate with a found percent error of 3.96%.