57 T= 4.6 N
60 x=-1.18 m, b. 1.35 s, c 3.5 m/s
67 a. T1= 14000N, b. T2 = 11000N, Fc= 2700N toward counterweight
71 a. 4.55m/s^2, b. 2.59 m/s^2
74a. 466N, b. 527N, c. 1050N, d. N always equals 2T so 932N, 1050N, 1860N and 2110 N
optional
63 F= 566N, b. 1130N
64a. 4.9m/s^2, b and c. a= 2m/s^2 , T= 120N
65 1.8000N
Friday, November 7, 2008
Tuesday, November 4, 2008
Solutions to problems due 11/7
9. b. 1.6 m/s2 at 50 degress
10. b. 088 m/s2 at 11 degrees
17 a.b.T1=77N, T2 = 44 N, c. T1= 199 N, T2= 150 N, T3= 54N
18. 108 N
19.1180N
23. 16N
26. T= 13 N
27. T= 42N, N= 72N, c. a=-5m/s2
34. 10m/s2
39 a. 0.74 m/s2, b. 7.3 m/s2
36. a. a(sled) = 0.62 m/s2, b. a(girl) = 0.13 m/s2, c. x=2.6m
38. F= 0.0022N
44. b)N= 49N
46. N=2.2*10^5 N, b. T=5.0*10^4N
48. a. a=0.970 m/s2, b. T=11.6 N, T2= 34.9 N.
10. b. 088 m/s2 at 11 degrees
17 a.b.T1=77N, T2 = 44 N, c. T1= 199 N, T2= 150 N, T3= 54N
18. 108 N
19.1180N
23. 16N
26. T= 13 N
27. T= 42N, N= 72N, c. a=-5m/s2
34. 10m/s2
39 a. 0.74 m/s2, b. 7.3 m/s2
36. a. a(sled) = 0.62 m/s2, b. a(girl) = 0.13 m/s2, c. x=2.6m
38. F= 0.0022N
44. b)N= 49N
46. N=2.2*10^5 N, b. T=5.0*10^4N
48. a. a=0.970 m/s2, b. T=11.6 N, T2= 34.9 N.
Sunday, November 2, 2008
Some odds and ends:
Recommended AP Physics C Study Guides:
5 Steps to a 5 by Greg Jacobs, Joshua Schulman, publisher: McGraw Hill
Physics C by Mooney, publisher: People’s Publishing
There’s a fun reading in our textbook on p.533 about walking on coals and more.
A physics game about balanced forces: http://www.vectorpark.com/levers/
5 Steps to a 5 by Greg Jacobs, Joshua Schulman, publisher: McGraw Hill
Physics C by Mooney, publisher: People’s Publishing
There’s a fun reading in our textbook on p.533 about walking on coals and more.
A physics game about balanced forces: http://www.vectorpark.com/levers/
Unit 3 Key dates
Test -- Dec. 12
Terminal Velocity Lab –Nov. 21
Homework Dates:
Due Date Assignment
Tue 11/4 ---Read sections 5.1-5.7
Wed. 11/5 ---Read section 5.8 - pay particular attention to sample problem 5.10
Fri. 11/7---Recommended: Q 1-15, E&P 9, 10, 17, 18, 19, 23, 26, 27, 34, 39, Required: E&P: 36, 38, 44, 46,48
Wed. 11/12----Required 57, 60, 67, 71, 74, Additional Optional 63, 64, 65
Fri 11/21----Read sections 6.1-6.3
Tue 12/2---Recommended: Q 1-8, E&P 2, 3, 4, 14, 44, 45, Required: 7, 17, 21, 23, 27, 31*, 33*, *express answers in terms of ma, mb, μs, μf, θ, Additional Optional: 25, 26, 34, 37
Fri 12/5--Read section 6-4, Recommended: Q 9-14, E&P 51, Required: 52, 55, 64, 66, Additional Optional: 68
Mon 12/8---Required 58, 65 (express answer in terms of T, r and m)
Tue 12/9---2 Free Response Questions
Terminal Velocity Lab –Nov. 21
Homework Dates:
Due Date Assignment
Tue 11/4 ---Read sections 5.1-5.7
Wed. 11/5 ---Read section 5.8 - pay particular attention to sample problem 5.10
Fri. 11/7---Recommended: Q 1-15, E&P 9, 10, 17, 18, 19, 23, 26, 27, 34, 39, Required: E&P: 36, 38, 44, 46,48
Wed. 11/12----Required 57, 60, 67, 71, 74, Additional Optional 63, 64, 65
Fri 11/21----Read sections 6.1-6.3
Tue 12/2---Recommended: Q 1-8, E&P 2, 3, 4, 14, 44, 45, Required: 7, 17, 21, 23, 27, 31*, 33*, *express answers in terms of ma, mb, μs, μf, θ, Additional Optional: 25, 26, 34, 37
Fri 12/5--Read section 6-4, Recommended: Q 9-14, E&P 51, Required: 52, 55, 64, 66, Additional Optional: 68
Mon 12/8---Required 58, 65 (express answer in terms of T, r and m)
Tue 12/9---2 Free Response Questions
Unit Three: Newton’s Laws of Motion – Five Weeks
Chapters 5 and 6
Goals:
1. Static Equilibrium (First Law)
a. Students should be able to analyze situations in which a particle remains at rest, or moves with constant velocity, under the influence of several forces.
2. Dynamics of a Single Body (Second Law)
a. Students should understand the relation between the force that acts on a body and the resulting change in the body’s velocity so they can:
(1) Calculate, for a body moving in one direction, the velocity change that results when a constant force F acts over a specified time interval.
(2) Calculate, for a body moving in one dimension, the velocity change that results when a force F(t) acts over a specified time interval.
(3) Determine, for a body moving in a plane whose velocity vector undergoes a specified change over a specified time interval, the average force that acted on the body.
b. Students should understand how Newton’s Second Law, Fnet = ma, applies to a body subject to forces such as gravity, the pull of strings, or contact forces, so they can:
(1) Draw a well-labeled diagram showing all real forces that act on the body.
(2) Write down the vector equation that results from applying Newton’s Second Law to the body, and take components of this equation along appropriate axes.
c. Students should be able to analyze situations in which a body moves with specified acceleration under the influence of one or more forces so they can determine the magnitude and direction of the net force, or of one of the forces that makes up the net force, in situations such as the following:
(1) Motion up or down with constant acceleration (in an elevator, for example).
(2) Motion in a horizontal circle (e.g., mass on a rotating merry-go-round, or car rounding a banked curve).
(3) Motion in a vertical circle (e.g., mass swinging on the end of a string, cart rolling down a curved track, rider on a Ferris wheel).
d. Students should understand the significance of the coefficient of friction so they can:
(1) Write down the relationship between the normal and frictional forces on a surface.
(2) Analyze situations in which a body slides down a rough inclined plane or is pulled or pushed across a rough surface.
(3) Analyze static situations involving friction to determine under what circumstances a body will start to slip, or to calculate the magnitude of the force of static friction.
e. Students should understand the effect of fluid friction on the motion of a body so they can:
(1) Find the terminal velocity of a body moving vertically through a fluid that exerts a retarding force proportional to velocity.
(2) Describe qualitatively, with the aid of graphs, the acceleration, velocity and displacement of such a particle when it is released from rest or is projected vertically with specified initial velocity.
3. Systems of Two or More Bodies (Third Law)
a. Students should understand Newton’s Third Law so that, for a given force, they can identify the body on which the reaction force acts and state the magnitude and direction of this reaction.
b. Students should be able to apply Newton’s Third Law in analyzing the force of contact between two bodies that accelerate together along a horizontal or vertical line, or between two surfaces that slide across one another.
c. Students should know that the tension is constant in a light string that passes over a massless pulley and should be able to use this fact in analyzing the motion of a system of two bodies joined by a string.
d. Students should be able to solve problems in which application of Newton’s Laws leads to two or three simultaneous linear equations involving unknown forces or accelerations.
Goals:
1. Static Equilibrium (First Law)
a. Students should be able to analyze situations in which a particle remains at rest, or moves with constant velocity, under the influence of several forces.
2. Dynamics of a Single Body (Second Law)
a. Students should understand the relation between the force that acts on a body and the resulting change in the body’s velocity so they can:
(1) Calculate, for a body moving in one direction, the velocity change that results when a constant force F acts over a specified time interval.
(2) Calculate, for a body moving in one dimension, the velocity change that results when a force F(t) acts over a specified time interval.
(3) Determine, for a body moving in a plane whose velocity vector undergoes a specified change over a specified time interval, the average force that acted on the body.
b. Students should understand how Newton’s Second Law, Fnet = ma, applies to a body subject to forces such as gravity, the pull of strings, or contact forces, so they can:
(1) Draw a well-labeled diagram showing all real forces that act on the body.
(2) Write down the vector equation that results from applying Newton’s Second Law to the body, and take components of this equation along appropriate axes.
c. Students should be able to analyze situations in which a body moves with specified acceleration under the influence of one or more forces so they can determine the magnitude and direction of the net force, or of one of the forces that makes up the net force, in situations such as the following:
(1) Motion up or down with constant acceleration (in an elevator, for example).
(2) Motion in a horizontal circle (e.g., mass on a rotating merry-go-round, or car rounding a banked curve).
(3) Motion in a vertical circle (e.g., mass swinging on the end of a string, cart rolling down a curved track, rider on a Ferris wheel).
d. Students should understand the significance of the coefficient of friction so they can:
(1) Write down the relationship between the normal and frictional forces on a surface.
(2) Analyze situations in which a body slides down a rough inclined plane or is pulled or pushed across a rough surface.
(3) Analyze static situations involving friction to determine under what circumstances a body will start to slip, or to calculate the magnitude of the force of static friction.
e. Students should understand the effect of fluid friction on the motion of a body so they can:
(1) Find the terminal velocity of a body moving vertically through a fluid that exerts a retarding force proportional to velocity.
(2) Describe qualitatively, with the aid of graphs, the acceleration, velocity and displacement of such a particle when it is released from rest or is projected vertically with specified initial velocity.
3. Systems of Two or More Bodies (Third Law)
a. Students should understand Newton’s Third Law so that, for a given force, they can identify the body on which the reaction force acts and state the magnitude and direction of this reaction.
b. Students should be able to apply Newton’s Third Law in analyzing the force of contact between two bodies that accelerate together along a horizontal or vertical line, or between two surfaces that slide across one another.
c. Students should know that the tension is constant in a light string that passes over a massless pulley and should be able to use this fact in analyzing the motion of a system of two bodies joined by a string.
d. Students should be able to solve problems in which application of Newton’s Laws leads to two or three simultaneous linear equations involving unknown forces or accelerations.
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