MCAT Physics Question — Model Trains
 by
 Sep 29, 2017
 MCAT Question of the Day
Two model trains are propelled along a straight, frictionless track by electric motors. Train X has a total mass of 100g and is moving at speed v. Train Y has a total mass of 10g and is moving at speed 3v. The ratio of the kinetic energies of Train X to Train Y is:
A. 10:9
B. 9:10
C. 10:3
D. 1:9
Click for Explanation
The kinetic energy equation is Ekinetic = ½ mv2. We can plug in the values given and set up a ratio to answer the question.
E_{X} = ½ (100)(v)^{2}
E_{Y} = ½ (10)(3v)^{2} = ½ (10)(9v^{2})
E_{X} / E_{Y} = ½ (100)(v)^{2} / ½ (10)9v^{2}
E_{X} / E_{Y} = (100)(v)^{2} / (10)9v^{2}
E^{X} / E^{Y} = (10)(v)^{2} / 9v^{2}
E_{X} / E_{Y} = 10 / 9
Thus choice (A), 10:9 is the correct answer.
Want more MCAT practice?
We’ve got options for every schedule and learning style!
From the best online MCAT course created by top instructors with 524+ MCAT scores to the most representative fulllength practice exams and private tutoring, we can custom tailor your MCAT prep to your goals!
Not sure which option is right for you? Schedule a free MCAT consultation with an MCAT expert using the form below. No obligation, just expert advice.
Search the Blog
Free Consultation
Interested in our Online MCAT Course, OneonOne MCAT Tutoring or Med admissions packages? Set up a free consultation with one of our experienced Senior Student Advisors.
Schedule NowPopular Posts

MCAT Blog How to Review MCAT FullLengths
Free MCAT Practice Account
Need great MCAT practice?Get the most representative MCAT practice possible when you sign up for our free MCAT Account, which includes a halflength diagnostic exam and one of our fulllength MCAT practice exams.
Learn More
Submit a Comment