AN IMPORTANT NOTE:
You now should have a good understanding of the graphical representation of uniformly accelerated motion (the position, velocity and acceleration time graphs) and recognize the equations that describe that motion. Make sure that you do. The next step is to apply those equations to problems that give you only partial information and ask you to determine the rest. For example you may know the acceleration, the initial velocity and the distance traveled, but not know the final velocity. The equations allow you to get the additional information if you use the correct information, which is not always given explicitly, and the equations that describe the motion. In solving these problems I will insist (until you develop a habit of writing down all the information, equations used and the steps taken) that you use the template that can be found on the web. There will be a shortened version of that page for the shorter problems. These problems are the first stumbling block for students taking general physics, so you must work diligently on the the assigned reading and problems if you wish to avoid serious difficulties. As tedious as it might seem, approaching these problems in a systematic way is critical. In grading your work I try to follow the logic of your solution. If there is no logic to follow and I am left guessing as to how you obtained the correct answer points will be deducted, although the final answer may be correct.
1. Do Ch 2 problems 14, 25, 32 and 51. Use the problem solving template for these problems. I will discuss their use in class. Don't leave these until the day they are to be turned in as they will need a little thought.
2. Read the text: Chapter 3 up to section 3.4 and if your trig skills are rusty go through Appendix III at the end of the Activity Guide. Chapter 3 will help with the concept of vectors that may be giving you difficulties and with calculating components of vectors.
3. Do Homework for Unit 6: Projectile Motion from the activity guide. Some of the questions are tricky so you have to understand the use of kinematics equations and projectile motion well to get them right.
4. Do additional Unit 6 problems 6-1 to 6-3 and 7-1 below.
Additional Unit 6 Problems
6-1 A car traveling on a horizontal road is seen shoot off the edge of a vertical cliff that is 30m high and lands 45m from the base of the cliff. How fast was the car traveling at the cliff's edge?
6-2 A penny is pushed off the end of a table and lands a short distance from the foot of the table. a) How much further from the base of the table would it land if its horizontal velocity was doubled? b) How much further from the base would it land if the height of the table was doubled? c) How much further from the base would it land if the acceleration of gravity was halved?
6-3 A human cannonball is fired from a cannon at an angle of 60 degrees from horizontal with a velocity of 20m/s. a) If the net is placed 5.00m below the mouth of the cannon, what are the horizontal and vertical velocities of the human cannonball when she lands in the net? b) What is her resultant velocity? c) How far from the cannon in the +x direction should the net be placed?
Due Thursday June 14th:
The Measurement Contest.
EITHER: Measure the height, from ground level, of the NE corner of Smith Hall. Remember this is an indirect measurement so don't make any direct measurements on the building itself. You will be given a handout for this activity in class and I will answer any questions you may have then. The reports are due at the beginning of class Thursday June 14th. If we move along fairly quickly in class I will give you class time on Tuesday or Wednesday to take measurements.
OR
In case you you don't care for the first assignment, estimate the volume flow of water in the Ohio River at Huntington. There will be no hints given with this assignment.
Assignment 2 due Friday June 17th.
1. Read the text: Chapter 4 sections 4-1, 4-2, 4-3 and 4-4.
2. Do Question 7-1 below.
3. Do the homework for Unit 7 in the Lab Manual.
Unit 7 Problems
7-1) A pair of twins find themselves locking arms while facing each other in outer space where there are no gravitational or friction forces on them. A wise being has assigned a standard physics coordinate system in outer space far away from any massive bodies. The twins are moving along the x-axis of this coordinate system with identical CO2 cartridges strapped to their backs. These cartridges can apply thrust forces that act in opposite directions.
There are four possibilities for on and off conditions for the cartridges:
A. Both cartridges are on C. Only Maria's cartridge is on (L->R thrust)
B. Both cartridges are off D. Only Martina's cartridge is on (R–> L thrust)
Use Newton's second law to choose the letters A, B, C, or D that describe combinations which could keep the twins moving as described in each statement below. You may choose one or more letters in each case.
1. The twins are moving toward the right. Which force combinations could slow them down at a steady rate (constant acceleration)?
2. The twins are slowing down at a steady rate and have an acceleration to the right. Which force combinations could
account for this motion?3. Which force combinations could keep the twins moving toward the right and speeding up at a steady rate (constant acceleration)?
4. Which force combinations could keep the twins moving toward the left and speeding up at a steady rate (constant acceleration)?
5. The twins are moving toward the left. Which force combinations could slow them down at a steady rate (constant acceleration)?
6. Which force combinations could keep the twins moving toward the right at a steady (constant) velocity?
7. The twins were started from rest and pushed until they reached a steady (constant) velocity toward the right. Which force combinations could keep the twins moving at this velocity?