2021 PHYSICS 7C(大学物理1）(大连理工大学) 最新满分章节测试答案

本答案对应课程为:点我自动跳转查看
本课程起止时间为:2021-03-01到2021-05-24
本篇答案更新状态:已完结

【作业】01 Motion Along a Straight Line Homework set 1

1、 问题:Please see the attachment 
评分规则: 【 Requirement:    1. Language in English.   2. Necessary analysis, equation or formular.    3. Necessary deducing process.    4.   Correct result.
】

01 Motion Along a Straight Line test 1

1、 问题: Which of the following is a scalar quantity:
选项：
A:speed
B:time
C:length 
D:instantaneous acceleration 
E:instantaneous velocity 
F:average velocity 
G:average acceleration 
H:magnitude of position vector
I:none of the above
答案: 【speed;
time;
length ;
magnitude of position vector】

2、 问题:In right handed coordinate system which axis is considered to be positive?
选项：
A:The thumb is z-axis, fingers curled from y-axis to x-axis
B:The thumb is x-axis, fingers curled from z-axis to y-axis
C:The thumb is y-axis, fingers curled from x-axis to z-axis
D: The thumb is z-axis, fingers curled from x-axis to y-axis
E:The thumb is x-axis, fingers curled from y-axis to z-axis
F:The thumb is y-axis, fingers curled from z-axis to x-axis
G:none of the above
答案: 【 The thumb is z-axis, fingers curled from x-axis to y-axis;
The thumb is x-axis, fingers curled from y-axis to z-axis;
The thumb is y-axis, fingers curled from z-axis to x-axis】

3、 问题:What is the magnitude of the Cartesian vector having the x, y and z axis components to be A, B and C?
选项：
A:Square root of the sum of squares each A, B and C
B:Square of the squares each A, B and C
C:Cube root of the squares each A, B and C
D:Cube of the squares each A, B and C
E:none of the others
答案: 【Square root of the sum of squares each A, B and C】

4、 问题:A physics professor leaves her house and walks along the sidewalk toward campus. After 5 min it starts to rain and she returns home. Her distance from her house as a function of time is shown in Fig. At Point ___( fill in the labeled points I/ II/ III/ IV/ V) is her velocity increasing in magnitude.
选项：
A:II
B:I
C:III
D:IV
E:V
F:none of the others
答案: 【II】

5、 问题:A physics professor leaves her house and walks along the sidewalk toward campus. After 5 min it starts to rain and she returns home. Her distance from her house as a function of time is shown in Fig.  At Point ___( fill in the labeled points I/ II/ III/ IV/ V) is her velocity zero. 
选项：
A:IV
B:I
C:II
D:III
E:V
F:none of the others
答案: 【IV】

6、 问题:The figure shows a position-versus-time graph of the motion of a car. Describe the velocity and acceleration during segments OA, AB, and BC. Which item is Not correct?
选项：
A:In segment OA, the velocity is positive and constant.
B:In segment OA, there is no acceleration.
C:In segment AB, the velocity is increasing.
D:In segment AB, there must be acceleration.
E:In segment BC, the velocity is not constant. 
F:In segment BC, this velocity is greater in magnitude than the velocity in segment OA.
答案: 【In segment BC, the velocity is not constant. 】

7、 问题:A speeder traveling at a constant speed of 100 km/hr passes a waiting police car that immediately starts from rest and accelerates at a constant 2.5 m/s^2 How long will it take for the police car to catch the speeder?
选项：
A: 22.2 s
B: 23.3 s
C: 24.8 s
D: 21.4 s
E:25.1 s
F:20.2 s
答案: 【 22.2 s】

8、 问题:A speeder traveling at a constant speed of 100 km/hr passes a waiting police car that immediately starts from rest and accelerates at a constant 2.5 m/s^2. How fast will the police car be traveling when it catches the speeder?
选项：
A: 200 km/hr
B: 210 km/hr
C: 220 km/hr
D: 190 km/hr
E:180 km/hr
F:230 km/hr
G:240 km/hr
答案: 【 200 km/hr】

9、 问题:The acceleration of a bus is given by a(t) =α*t, where α = 1.2 m/s^3. If the bus’s velocity at time t = 1.0s is 5.0 m/s, what is its velocity at time t = 2.0 s?
选项：
A:6.8 m/s
B:5.6 m/s
C:4.5 m/s
D:7.6 m/s
E:8.6 m/s
F:5.1 m/s
G:5.3 m/s
答案: 【6.8 m/s】

10、 问题:The acceleration of a bus is given by a(t) =α*t, where α = 1.2 m/s^3. If the bus’s position at time t = 1.0 s is 6.0 m, what is its position at time t = 2.0 s?
选项：
A:11.8 m
B:9.5 m
C:10 m
D:12.7 m
E:13.2 m
F:14.1 m
G:14.6 m
H:9.1 m
答案: 【11.8 m】

【作业】02 Motion in Two or Three Dimensions Homework Set 2

1、 问题:Please see attached file.
评分规则: 【 Requirement:    1. Language in English.   2. Necessary analysis, equation or formular.    3. Necessary deducing process.   4.  Correct result.
】

02 Motion in Two or Three Dimensions Test 2

1、 问题:An object that’s moving with constant speed travels once around a circular path. Which of the following is/are true concerning this motion?I. The displacement is zero. II. The average speed is zero. III. The acceleration is zero.
选项：
A:I only
B:I and II only
C:I and III only
D:III only
E:II and III only
F:II only
答案: 【I only】

2、 问题: A rock is thrown off a 30 m cliff at a 45° angle above the horizontal. Which is the following is true regarding the acceleration of the rock? (air resistance is negligible)
选项：
A:The acceleration will be of magnitude g and have both horizontal and vertical components.
B: At the peak of the rock’s path, the magnitude of acceleration will be half of what it was when the rock was initially thrown. 
C: The acceleration will be of magnitude g and in a downward direction.
D: The acceleration will be downward during the rock’s ascent and upward during the rock’s descent. 
E:The acceleration will increase throughout the rock’s flight.
F:None of the others.
答案: 【 The acceleration will be of magnitude g and in a downward direction.】

3、 问题:A stone is thrown horizontally with an initial speed of 30 m/s from a bridge. Find the stone’s total speed when it enters the water 4 seconds later. (Ignore air resistance.)
选项：
A:30 m/s
B: 40 m/s 
C:50 m/s
D: 60 m/s
E: 70 m/s
F: 55 m/s
G: 65 m/s
答案: 【50 m/s】

4、 问题:Which one of the following statements is true concerning the motion of an ideal projectile launched at an angle of 45°to the horizontal?
选项：
A:The acceleration vector points opposite to the velocity vector on the way up and in the same direction as the velocity vector on the way down. 
B:The speed at the top of the trajectory is zero.
C: The object’s total speed remains constant during the entire flight.
D:The horizontal speed decreases on the way up and increases on the way down. 
E:The vertical speed decreases on the way up and increases on the way down.
F:None of the others.
答案: 【The vertical speed decreases on the way up and increases on the way down.】

5、 问题:The position of an object moving in a straight line is given by the equation x = (3t^3 + 7t + 5) m, where t is in seconds. What is the object’s acceleration at time t = 5 seconds?   __ m/s^2
选项：
A:415 
B:232
C:115
D:90
E:35
F:42
G:230
H:121
答案: 【90】

6、 问题:The earth has a radius of 6380 km and turns around once on its axis in 24 h. What is the radial acceleration of an object at the earth’s equator?  _ m/s^2
选项：
A:0.034