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MCAT Physics: Elastic, Inelastic, and Perfectly Inelastic Collisions
Solving collision problems the traditional way, that is the way you were taught in physics class, can be both frustrating and time-consuming. So for the MCAT, instead of drawing diagrams and vectors, just memorize this helpful information:
When analyzing collisions, use the conservation of momentum equation because momentum is conserved in all collisions and does not change within the system:
total momentum before = total momentum after
m1v1 + m2v2 = m1v1’ + m2v2’
When lighter objects collide into heavier objects, lighter objects bounce backward; thus, the velocity after the collision is negative.
When heavier objects collide into lighter objects, lighter objects get pushed forward; thus, the velocity after the collision is positive.
For elastic collisions:
Total momentum and total kinetic energy are conserved
These collisions are common among subatomic particles
For inelastic collisions:
Only total momentum is conserved
Kinetic energy is lost mostly as heat, sound, or deformation
For perfectly inelastic collisions (an MCAT favorite):
Only total momentum is conserved
These collisions always lose maximum kinetic energy
The objects stick together, so combine the objects’ masses post-collision:
m1v1 + m2v2 = (m1+ m2)v’
We hope you found this information helpful. If there’s any topic you would like us to tackle, please let us know.
Click here for: MCAT Physics Equations Sheet
Good luck with your journey to medical school.
Gold Standard MCAT Prep
MCAT Prep since 1991 - Online since 2001: MCAT-prep.com
Solving collision problems the traditional way, that is the way you were taught in physics class, can be both frustrating and time-consuming. So for the MCAT, instead of drawing diagrams and vectors, just memorize this helpful information:
When analyzing collisions, use the conservation of momentum equation because momentum is conserved in all collisions and does not change within the system:
total momentum before = total momentum after
m1v1 + m2v2 = m1v1’ + m2v2’
When lighter objects collide into heavier objects, lighter objects bounce backward; thus, the velocity after the collision is negative.
When heavier objects collide into lighter objects, lighter objects get pushed forward; thus, the velocity after the collision is positive.
For elastic collisions:
Total momentum and total kinetic energy are conserved
These collisions are common among subatomic particles
For inelastic collisions:
Only total momentum is conserved
Kinetic energy is lost mostly as heat, sound, or deformation
For perfectly inelastic collisions (an MCAT favorite):
Only total momentum is conserved
These collisions always lose maximum kinetic energy
The objects stick together, so combine the objects’ masses post-collision:
m1v1 + m2v2 = (m1+ m2)v’
We hope you found this information helpful. If there’s any topic you would like us to tackle, please let us know.
Click here for: MCAT Physics Equations Sheet
Good luck with your journey to medical school.
Gold Standard MCAT Prep
MCAT Prep since 1991 - Online since 2001: MCAT-prep.com
