MCAT Physics Question — Model Trains | Next Step Test Prep MCAT Physics Question — Model Trains | Next Step Test Prep

Fields marked with an * are required

Schedule a Free Tutoring Consultation

A Next Step Academic Manager will contact you within 1 business day or call us now at 888-530-6398.

Contact us

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

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

 

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.

 

EX = ½ (100)(v)2

EY = ½ (10)(3v)2 = ½ (10)(9v2)

 

EX / EY = ½ (100)(v)2 / ½ (10)9v2

EX / EY = (100)(v)2 / (10)9v2

EX / EY = (10)(v)2 / 9v2

EX / EY = 10 / 9

 

Thus choice (A), 10:9 is the correct answer.

 

Want more practice?

Fields marked with an * are required

Sign up for our MCAT Question of the Day!

X