Download 8th Grade Force and Motion

8th Grade Force and Motion - Forensic Physics Challenge Brief
Students will conduct a physical forensics investigation to help close a theoretical homicide case. Data will be
shared with the Bexar County Criminal Investigation Laboratory and the USAF Security Forces Center.
How can you use your knowledge of physics to close a theoretical homicide investigation and determine the
shooter, their location, type of weapon used, and relevant forces involved in the ballistics of a projectile?
Your project will include a multimedia presentation that includes the following:
Compare and contrast potential and kinetic energy.
 At which point was the potential energy of the projectile the greatest?
 How is the kinetic energy of a projectile related to its lethality?
 Determine the amount of chemical potential energy in each caliber of round collected at the crime
scene.
 Also determine the muzzle energy of each type of projectile.
 Use this data to make a determination about the round that led to death.
Calculate average speed using distance and time measurements.
 What was the average speed of each of the rounds fired?
 Use this data to determine the distance the shooter was away from the victim.
 Use this data to make a determination about the round that led to death.
Measure and graph changes in motion.
 Graph the speed and motion of each projectile and make a determination about the round that
led to death.
Demonstrate energy transformations such as energy in a flashlight battery changes from chemical energy to
electrical energy to light energy.
 Describe the energy transformations involved in the firing of a chemically propelled projectile
such as a bullet.
 Include the following types of energy transformations:
o Potential to Kinetic to Potential
o Mechanical to Thermal to Chemical to Kinetic
o Rotational Mechanical to Potential
o and any others you can define.
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Contrast situations where work is done with different amounts of force to situations where no work is done
such as moving a box with a ramp and without a ramp, or standing still.
 Describe the work done on the victim by the bullet.
Demonstrate and calculate how unbalanced forces change the speed or direction of an object's motion.
 Describe the balanced/unbalanced forces involved with the firing of a projectile from the moment
it is loaded in the chamber of the firearm to the moment of projectile stoppage.
 Also calculate the net force applied to a bullet in flight, and the net force of the projectile's impact
on the victim.
Differentiate between speed, velocity, and acceleration.
 Determine the velocity and trajectory of each round in flight from the muzzle of the firearm to the
impact point.
 Also describe the acceleration of the round at each point in the projectile's path.
Investigate and describe applications of Newton's law of inertia, law of force and acceleration, and law of
action-reaction such as in vehicle restraints, sports activities, amusement park rides, Earth's tectonic
activities, and rocket launches.
 Newton's First Law: Use Newton's First Law to describe why a projectile in motion will not change
course unless an unbalanced force is applied to it.
 Newton's Second Law: Describe the force of each projectile using the mass and acceleration of
each. Determine which projectile applied the most force to the victim using F=MA.
 Newton's Third Law: Describe how Newton's Third Law applies to the discharge of a firearm.
Include details about recoil and projectile motion down the barrel of the firearm.
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