MCAT Physics Quiz

Once you’re familiar with the physics that will be tested on the MCAT, try out this MCAT Physics Quiz.

Question 1
Mechanical advantage and efficiency are both ratios. Which of the following is true regarding the quantities used in these ratios?
A. Mechanical advantage compares values of work; efficiency compares values of power.
B. Mechanical advantage compares values of forces; efficiency compares values of work.
C. Mechanical advantage compares values of power; efficiency compares values of energy.
D. Mechanical advantage compares values of work; efficiency compares values of forces.

B: Mechanical advantage is a ratio of the output force generated given a particular input force. Efficiency is a ratio of the useful work performed by a system compared to the work performed on the system.

Question 2
Two wooden balls of equal volume but different density are held beneath the surface of a container of water. Ball A has a density of 0.5 g/cm^3, and ball B has a density of 0.7 g/cm^3. When the balls are released, they will accelerate upward to the surface. What is the relationship between the acceleration of ball A and that of ball B?
A. Ball A has the greater acceleration.
B. Ball B has the greater acceleration.
C. Balls A and B have the same acceleration.
D. It cannot be determined from information given.

A: Using Newton’s second law, F(net) = ma, we obtain the follow-ing equation:
F(buoy) − mg = ma
(F(buoy) − mg) / m = (F(buoy) / m) − g
Both balls experience the same buoyant force because they are in the same liquid and have the same volume (F(buoy) = ρVg). Thus, the ball with the smaller mass experiences the greater acceleration. Because both balls have the same volume, the ball with the smaller density has the smaller mass (m = ρV), which is ball A.

Question 3
F represents the electrostatic force exerted on charged particle S by charged particle R.
mcat physics
In the figure, the magnitude of the electric force on R due to S is:
A. F/2.
B. F.
C. 2F.
D. 4F.

B: According to Newton’s third law, if R exerts a force on S, then S exerts a force with equal magnitude but opposite direction back on R. Therefore, the magnitude of the force on R due to S is F.

Question 4
Each of the resistors shown carries an individual resistance of 4 Ω.
mcat physics
Assuming negligible resistance in the wire, what is the overall resistance of the circuit?
A. 16 Ω
B. 8 Ω
C. 4 Ω
D. 3 Ω

D: The resistance of the three resistors wired in series is equal to the sum of the individual resistances (12 Ω). This means that the circuit functionally contains a 12 Ω resistor and a 4 Ω resistor in parallel. To determine the overall resistance of this system, use this formula:
1/R(p) = 1/R(1) + 1/R(2) = 1/(12Ω)  + 1/(4Ω) = (1 + 3)/(12Ω) –> R(p) = 3Ω

Question 5
A scientist looks through a microscope with two thin lenses with m1 = 10 and m2 = 40. What is the overall magnification of this microscope?
A. 0.25
B. 30
C. 50
D. 400

D: The overall magnification of a system of multiple lenses is simply the product of each lens’s magnification. In this case, that is 10 × 40 = 400.