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