AP-24 Physics Mech Set 1

University:
Harvard University
Course:
PHYSICS 19 | Introduction to Theoretical Physics
Academic year:

2024
Views:

139

Pages:

16
Author:

Gi Tae PARK

2024 AP Physics C: Mechanics ® Free-Response Questions Set 1 © 2024 College Board. College Board, Advanced Placement, AP, AP Central, and the acorn logo are registered trademarks of College Board. Visit College Board on the web: collegeboard.org. AP Central is the official online home for the AP Program: apcentral.collegeboard.org. AP® Physics C: Mechanics 2024 Free-Response Questions ADVANCED PLACEMENT PHYSICS C TABLE OF INFORMATION CONSTANTS AND CONVERSION FACTORS Proton mass, m p 1.67 10 27 kg Neutron mass, mn 1.67 10 27 kg Electron mass, me 9.11 10 31 kg 6.02 10 23 mol 1 Avogadro’s number, N 0 R Universal gas constant, 8.31 J (mol t4, the system oscillates with frequency f. The support holding the string is raised, and the procedure is then repeated using a new string of length 2 . (c) Indicate how the new frequency of oscillation f2 of the system on the new string of length 2 will compare to the frequency of oscillation f from the original procedure. _____ f2 > f _____ f2 < f _____ f2 = f Briefly justify your answer. GO ON TO THE NEXT PAGE. © 2024 College Board. Visit College Board on the web: collegeboard.org. 8 AP® Physics C: Mechanics 2024 Free-Response Questions Begin your response to QUESTION 2 on this page. 2. A student drops a cylinder of mass m from rest. The air exerts a drag force of magnitude Fdrag on the cylinder, as shown in Figure 1. The student models the magnitude of the drag force as Fdrag = bv2 , where v is the speed of the cylinder and b is a positive constant with appropriate units. (a) Derive, but do NOT solve, a differential equation that could be used to determine the speed v of the cylinder as a function of time t . Express your answer in terms of given quantities and physical constants, as appropriate. GO ON TO THE NEXT PAGE. © 2024 College Board. Visit College Board on the web: collegeboard.org. 9 AP® Physics C: Mechanics 2024 Free-Response Questions Continue your response to QUESTION 2 on this page. (b) The student correctly sketches the speed v of the cylinder as a function of time t , as shown in Figure 2 . i. Draw a vertical line on the sketch in Figure 2 to indicate the earliest time at which Fdrag on the cylinder is equal to the magnitude of the weight of the cylinder. Label this time as t1 on the time axis. ii. Justify the location of t1. Explicitly reference appropriate features of the sketch in Figure 2 . (c) Rather than dropping the cylinder from rest, the student throws the cylinder upward with a nonzero initial speed. The cylinder is in the same orientation as when the cylinder was previously dropped. The student allows the cylinder to fall toward the ground. Indicate whether the magnitude of the cylinder’s maximum downward speed after being thrown upward would be greater than, less than, or equal to the maximum speed vmax in Figure 2 . _____ Greater than _____ Less than _____ Equal to Briefly justify your answer. GO ON TO THE NEXT PAGE. © 2024 College Board. Visit College Board on the web: collegeboard.org. 10 AP® Physics C: Mechanics 2024 Free-Response Questions Continue your response to QUESTION 2 on this page. (d) The student conducts an experiment to better understand the relationship between maximum speed vmax and mass. The student collects data to determine the maximum speed for cylinders dropped from rest, each with 2 as a function of mass. the same physical size and shape but a different mass m. The student then graphs vmax i. Draw the best-fit line for the data. ii. Use the best-fit line to calculate an experimental value for b. GO ON TO THE NEXT PAGE. © 2024 College Board. Visit College Board on the web: collegeboard.org. 11 AP® Physics C: Mechanics 2024 Free-Response Questions Continue your response to QUESTION 2 on this page. A student claims that the magnitude of the maximum speed of a cylinder dropped from rest depends on the length of the cylinder. The student designs an experiment to collect data that can be used to provide evidence to support the claim. The student drops cylinders with the orientation shown in Figure 3. (e) The student has access to but does not have to use all of the following equipment. • Cylinder Set 1: cylinders of the same known length with different known masses • Cylinder Set 2 : cylinders of the same known mass with different known lengths • A motion detector that can measure velocity as a function of time i. Indicate two quantities that when graphed could be used to determine whether the length of the cylinder affects the maximum speed. Vertical axis: ______________ Horizontal axis: _______________ ii. Briefly describe how the quantities graphed could be used to determine the relationship between cylinder length and maximum speed. GO ON TO THE NEXT PAGE. © 2024 College Board. Visit College Board on the web: collegeboard.org. 12 AP® Physics C: Mechanics 2024 Free-Response Questions Begin your response to QUESTION 3 on this page. 3. A uniform rod of length L and mass m is attached to a pivot on a vertical pole, as shown in Figure 1. There is negligible friction between the rod and the pivot. A horizontal string connects Point Q on the rod to the pole. The rod makes an angle q with the pole. A block of mass 3m hangs from the rod at Point P. The center of mass of the rod is located at Point C. (a) On the following representation of the rod, draw and label the forces (not components) that are exerted on the rod. Each force must be represented by a distinct arrow that starts on and points away from the point at which the force is exerted on the rod. GO ON TO THE NEXT PAGE. © 2024 College Board. Visit College Board on the web: collegeboard.org. 13 AP® Physics C: Mechanics 2024 Free-Response Questions Continue your response to QUESTION 3 on this page. (b) In Figure 1, Point P is located 3 6 L from the pivot and Point Q is located L from the pivot. Derive an 8 8 equation for the tension FT in the horizontal string in terms of L , m, q , and physical constants, as appropriate. (c) The original string is replaced with a longer string that connects Point Q to a higher location on the vertical pole, as shown in Figure 2 . The angle q remains the same. How does the new tension FT, new compare with the original tension FT from part (b) ? Justify your reasoning. GO ON TO THE NEXT PAGE. © 2024 College Board. Visit College Board on the web: collegeboard.org. 14 AP® Physics C: Mechanics 2024 Free-Response Questions Continue your response to QUESTION 3 on this page. (d) A nonuniform rod is now attached to the pivot, as shown in Figure 3. There is negligible friction between the nonuniform rod and the pivot. The rod has a length of 1.2 m and a linear mass density l(x ) = A + Bx , where x is the distance from the pivot, A = 6.0 kg/m, and B = 10 .0 kg/m2. i. Calculate the mass of the rod. ii. Calculate the rotational inertia of the rod about the pivot. GO ON TO THE NEXT PAGE. © 2024 College Board. Visit College Board on the web: collegeboard.org. 15 AP® Physics C: Mechanics 2024 Free-Response Questions STOP END OF EXAM © 2024 College Board. Visit College Board on the web: collegeboard.org. 16