2018年AP物理1简答题真题+答案+PDF下载
1. (7 points, suggested time 13 minutes)
A spacecraft of mass m is in a clockwise circular orbit of radius R around Earth, as shown in the figure above.
The mass of Earth is upercase ME.
(a) In the figure below, draw and label the forces (not components) that act on the spacecraft. Each force must be represented by a distinct arrow starting on, and pointing away from, the spacecraft.
(b)
i. Derive an equation for the orbital period T of the spacecraft in terms of m, upercase M sub E upercase ME, R, and physical constants, as appropriate. If you need to draw anything other than what you have shown in part (a) to assist in your solution, use the space below. Do NOT add anything to the figure in part (a).
ii. A second spacecraft of mass 2m is placed in a circular orbit with the same radius R. Is the orbital period of the second spacecraft greater than, less than, or equal to the orbital period of the first spacecraft?
____Greater than ____Less than ____Equal to
Briefly explain your reasoning.
(c) The first spacecraft is moved into a new circular orbit that has a radius greater than R, as shown in the figure below.
Is the speed of the spacecraft in the new orbit greater than, less than, or equal to the original speed?
____ Greater than ____Less than ____Equal to
Briefly explain your reasoning.
2. (12 points, suggested time 25 minutes)
A group of students prepare a large batch of conductive dough (a soft substance that can conduct electricity) and then mold the dough into several cylinders with various cross-sectional areas A and lengths e. Each student applies a potential difference △V across the ends of a dough cylinder and determines the resistance R of the cylinder. The results of their experiments are shown in the table below.
(a) The students want to determine the resistivity of the dough cylinders.
i. Indicate below which quantities could be graphed to determine a value for the resistivity of the dough cylinders. You may use the remaining columns in the table above, as needed, to record any quantities (including units) that are not already in the table.
Vertical Axis: ________________________
Horizontal Axis: ________________________
ii. On the grid below, plot the appropriate quantities to determine the resistivity of the dough cylinders.Clearly scale and label all axes, including units as appropriate.
iii. Use the above graph to estimate a value for the resistivity of the dough cylinders.
(b) Another group of students perform the experiment described in part (a) but shape the dough into long rectangular shapes instead of cylinders. Will this change affect the value of the resistivity determined by the second group of students?
____Yes ____No
Briefly justify your reasoning.
(c) Describe an experimental procedure to determine whether or not the resistivity of the dough cylinders depends on the temperature of the dough. Give enough detail so that another student could replicate the experiment. As needed, include a diagram of the experimental setup. Assume equipment usually found in a school physics laboratory is available.
2018年AP物理1简答题真题余下省略！
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