2022-05-04 来源:
2018年AP力学(选择题+简答题)真题及答案下载(PDF)
以下为2018年AP力学选择题真题:
An object is moving along a straight line. The object’s velocity as a function of time is shown in the graph above.
Questions 1-2
1. During which of the labeled segments on the graph is the object moving but not accelerating?
(A) A
(B) B
(C) C
(D) D
(E) E
2. The object has a speed of 2 m/s at which of the following times?
(A)1 second only
(B) 6 seconds only
(C) 9 seconds only
(D) 4 s and 10 s only
(E) 1 s ,6 s , and 9 s
3. An object falls freely from rest under the influence of gravity. If air resistance is negligible, the ratio of the distances traveled during each 1-second time interval by the object during the first, second, and third seconds of its fall is
(A) 1:1:1
(B) 1:2:3
(C) 1:2:4
(D) 1:3:5
(E) 1:4:9
Questions 4-5
A sphere on the end of a string is released from rest at point X and swings through point Y to point Z, as shown in the figure above. Point Y is the lowest point for the sphere as it swings. Air resistance is negligible.
4. Four directions at point Z are indicated as Ⅰ,Ⅱ,Ⅲ, and Ⅳ in the figure above. Which of the arrows best indicates the direction of the acceleration of the sphere at point Z?
(A) Ⅰ
(B) Ⅱ
(C) Ⅲ
(D) Ⅳ
(E) The direction of the acceleration is undefined because the acceleration equals zero.
5. Four directions at point Y are indicated as Ⅰ,Ⅱ,Ⅲ, and Ⅳ in the figure above. DirectionsⅠ and Ⅲ are vertical,Ⅱand Ⅳ are horizontal, and Ⅰis directed along the string. Which of the following best indicates the direction of the acceleration of the sphere at point Y?
(A) Ⅰ
(B) Ⅱ
(C) Ⅲ
(D) Ⅳ
(E) The direction of the acceleration is undefined because the acceleration equals zero.
余下2018年AP力学选择题真题及答案省略!
2018年AP力学简答题真题:
1. A student sets up an experiment with a cart on a level horizontal track. The cart is attached with an elastic cord to a force sensor that is fixed in place on the left end of the track. A motion sensor is at the right end of the track, as shown in the figure above. The cart is given an initial speed of v0=2.0m/s and moves with this constant speed until the elastic cord exerts a force on the cart. The motion of the cart is measured with the motion detector, and the force the elastic cord exerts on the cart is measured with the force sensor. Both sensors are set up so that the positive direction is to the left. The data recorded by both sensors are shown in the graphs of velocity as a function of time and force as a function of time below.
(a) Calculate the mass m of the cart.
For time period from 0.50 s to 0.75 s, the force F the elastic cord exerts on the cart is given as a function of time t by the equation F=A sin(ωt), where A =6.3 N and ω= 12.6 rad/s .
(b) Using the given equation, show that the area under the graph above is 1.0 N•s.
(c) The experiment is repeated using a different cord that exerts a larger average force on the cart. The cart starts and ends with the same speeds as those in the original experiment. Will the area for the graph of force as a function of time for the new cord be greater than, less than, or equal to the area for that of the original cord?
____Greater than ____Less than ____Equal to
Justify your answer.
The elastic cord from the original experiment can be modeled as an ideal spring with force constant k .
(d) Derive an expression for the maximum change in length xMAX for the cord. Express your answer in terms of m, k,v0, and physical constants, as appropriate.
The student performs several trials of the experiment. For the first trial, the cart is empty. In each succeeding trial, a block is added to the cart. In all trials, the cart has an initial speed of 2.0 m/s , and the maximum change in length of the elastic cord is measured. The total mass M of the cart and the maximum change in length of the cord in each trial are recorded in the table below.
(e) Indicate below which quantities should be graphed to yield a straight line with a slope that could be used to calculate a numerical value for the force constant of the elastic cord k.
Verticalaxis:
Horizontal axis:
Use the remaining columns in the table on the previous page, as needed, to record any quantities that you indicated that are not given.
(f) Plot the data points for the quantities indicated in part (e) on the graph below. Clearly scale and label all axes, including units as appropriate. Draw a straight line that best represents the data.
(g) Use the best-fit line to calculate the force constant k of the elastic cord.
2018年AP力学简答题真题及答案解析,余下省略!
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