Lab Report Three
11/9/2021
Investigation Three
Section One
Guiding Question: Is the Collision Between Two Marbles Elastic?
Concepts:
In this lab, elastic and inelastic collisions in two dimensions were investigated. A system
exchanges momentum and energy when they collide with no interaction with outside objects. An
elastic collision conserves both momentum and total energy of the system. An inelastic collision
occurs when momentum is conserved in the collision, yet kinetic energy is lost. Kinetic energy
can be turned into other forms of energy and lost through heat, sound or friction.
Kinetic Energy is measured in Joules (J) and is defined as energy an object has while it is
in motion. Kinetic energy can never be a negative number. The following equation can be used
to calculate kinetic energy of an object: (½)mv2
Momentum is a vector quantity because it has both magnitude and direction. Momentum
is the product of mass and velocity of an object and therefore can be found with the following
equation: p = mv. Momentum can occur in both the X and Y direction and is expressed in units
of kg(m/s). In this experiment, momentum will only occur in the X direction as the marbles are
moving horizontally and not vertically.
The question “Is the Collision Between Two Marbles Elastic” can be answered by
comparing the initial and final kinetic energy of the marble system. In an elastic collision, all
kinetic energy is conserved or transferred while in an inelastic collision, kinetic energy is lost.
Section Two
Experimental Procedure:
To complete the experiment, each group member took a video of two marbles colliding
on a flat surface using a smartphone recording device. All videos were taken from an above
angle, looking down on the experiment so the collision of the marbles was captured in frame. A
tape measure or rule was placed near the edge of the video frame as a reference point. Marble
two was placed at inch six of the measuring tape (initial velocity will be zero). Marble one was
placed at the start of the measuring tape. Marble one was rolled towards marble two in a straight
line in order to create a collision. Marble one began to slow down after colliding with marble
two. Following the collision, marble two immediately started to move before eventually rolling
to a stop. The video recording ended when both marbles were stationary.