MCAT Physics Question — Object Acceleration
 by
 Oct 08, 2017
 MCAT Question of the Day
 Reviewed By: Liz Flagge
An object rests on a plane, with an angle of incline, θ, an acceleration due to gravity, g, and a coefficient of friction μ between the object and the plane. Which of the following gives the acceleration of the object?
A. a = g sin θ
B. a = g (sin θ – cos θ)
C. a = g (cos θ – μ sin θ)
D. a = g (sin θ – μ cos θ)
Click for Explanation
The force of gravity down the plane is given by F_{g} = mg sin θ. The frictional force is given by F_{f} = μ mg cos θ.
Thus, we can set up the overall equation:
F_{net} = F_{g} – F_{f}
Applying Newton’s Second Law, we can rewrite the equation as:
ma = F_{g} – F_{f}
Substituting the equations given for F_{f} and F_{g} we get:
ma = mg sin θ – μ mg cos θ
Canceling out “m” throughout the equation and factoring out the “g” leaves us with:
a = g (sin θ – μ cos θ)
Thus, choice (D) is the right 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 What's on the MCAT?

MCAT Blog How to Review MCAT Full Lengths
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