Physics 105: Elementary Mechanics and Heat

SUNY Cortland

Fall 2022

Homework

7.3

Due	Reading	Problems	Posted
Due	Reading	Problems	Posted
Aug. 29			Aug. 29
Aug. 31	Introduction and Chapter 1 and 2 1.1, 1.2, 1.4, 2.1-2.3.		Aug. 29
Sept. 2	Chapter 2 cont.: 2.4- 2.6	Sign next to your name on the check-off sheet in my office during office hours. Not sure when they are? Check the syllabus. Have a time conflict? Check the syllabus.	Aug. 29
Sept. 5	Labor day	No class	Aug. 29
Sept. 7	Chapter 2 cont. 2.7-2.8		Sept 6
Sept. 9	Chapter 4: 1-3, practice P&E2.64	Problem & Exercises (denoted as chapter.problem#): 1.1 (The speed limit...), 1.5 (Soccer fields...), 1.29 (How many heartbeats...), 1.32 (Calculate the approximate...), 2.3 (Find the folling for path C...), 2.9 (On May 26, 1934...), and 2.14(A football quarterback...)	Sept. 6
Sept. 12	No new reading, practice P&E2.24		Sept. 9
Sept. 14	No new reading, practice P&E2.50		Sept. 9
Sept. 16	Chapter 4: 4.4-4.6, practice P&E4.3	Chapter 2 Conceptual Questions: 2.16(If a subway...), 2.30(Consider the...). Problem and Exercises: 2.20(An olympic...) , 2.23(a light-rail...), 2.31, 2.34, 2.59, and 2.65 .	Sept. 9
Sept. 19	Chapter 4 cont., practice P&E4.3		Sept 19
Sept. 21	practice P&E4.20		Sept 19
Sept. 23	Chapter 3	Standing on the pedestrian path on the new Tappan Zee bridge (43m above the water) you throw a rock straight down toward the water (which may or may/not be legal) at 10m/s. Calculate and graph the velocity and position of the rock at 0.50s, 1.00s, 1.50s, and 2.00s. Be sure to clearly specify the coordinate system you are using. (a) Calculate the height of a cliff if it takes 2.35s for a rock to hit the ground after being thrown straight up at 4m/s. (b) How long would it take to reach the ground if thrown straight down at the same speed? A swimmer bounces stright up from a diving board and falls feet first into a pool. She leaves the diving board with a velocity of 4.00m/s up and her feet are 1.80m above the pool. (a) How long until she hits the water? (b) How high above the water do her feet get? (c) What is her velocity when she hits the water? A 63.0kg sprinter starts a race with an acceleration of 4.20m/s^2 (in the direction the runner is running). What is the net external force on the runner? A powerful motorcycle can produce an acceleration with a magnitude of 3.50m/s^2 while traveling at 90.0km/hr. At that speed the forces resisting motion total 400N. What force does the motorcycle exert on the ground to produce 3.50m/s^2 of acceleration? Note that the combine mass of the bike and rider is 235kg.	Sept 19
Sept. 26	Read 3.2-3.3, Practice P&E 3.4, 3.18, 3.20		Sept. 26
Sept. 28	Read 3.4-3.5, Practice P&E 3.25, 3.40		Sept. 28
Sept. 30	Read 4.5 and 4.7	Note new due date and 2 additional problems.	Sept. 28
Oct. 3	Read 4.5 and 4.7	Chapter 3 Problems and Exercises: 5, 10, 11, 16, 21a, 35 and An archer shoots an arrow at a target 70.0m away. She looses the arrow at a height of 120cm from the ground, the same height as the bull's-eye of the target. (a) What angle should she shoot the arrow to hit the bull's-eye if the arrow is travelling at 35.0m/s? (b) A tree standing half-way between the archer and the target has a narrow branch sticking out 4.7m above the ground. Will the arrow go above, below, or hit the tree-branch? Note that for the first 3 question (5, 10, 11) you must explain your process to get credit and for the last 3 questions (flight, broad jumper, and archer) be sure to include a sketch, show your work, and explain your logic. Chapter 4: Problems and Exercises: 23 and 34	Sept. 28
Oct. 5	Read 5.1-Static Friction		Oct. 21
Oct. 7	Read 5.1-Kinetic Friction	Work on practice exam	Oct. 21
Oct. 10	5.2-Drag		Oct. 21
Oct. 12	Review		Oct. 21
Oct. 14	Exam 1		Oct. 21
Oct. 17	Fall Break		Oct. 21
Oct. 19	Read 5.3-springs and restoring forces		Oct. 21
Oct. 21			Oct. 21
Oct. 24	Chapter 6.1-6.3		Oct. 21
Oct. 26	Chapter 6.4-6.5	First report due.	Oct. 21
Oct. 28	Chapter 7.1-7.3	4.42 (A 76.0kg person...), 5.4 (Suppose you have...), A baseball player with mass 79kg, sliding into second base, is retarded by a frictional force of magnitude 470N. What is the coefficient of kinetic friction between the player and the ground?, A 12N horizontal force pushes a block with mass 0.5kg against a vertical wall. The coefficient of static friction between the wall and the block is 0.60 and the coefficient of kinetic friction is 0.4. Assume that the block is not moving initially. Will the block move?, 5.17 ( consider the 52.0kg mountain...), 5.25 (calculate the velocity...), 5.31 (The lead in ...)	Oct. 21
Nov. 2			Nov. 3
Nov. 4	7.4-7.7		Nov. 3
Nov. 7	8.1-8.3		Nov. 3
Nov. 9	8.4	A 50kg wooden crate is being pushed up a ramp with a force of 100N (parallel to the ramp) and is initially moving up the ramp at 5.0m/s. The coefficient of kinetic friction is 0.3 and the ramp slopes up at an angle of 20deg from level ground. Will the crate speed up, slow down, or move at a steady pace? Be sure your answer is well supported. A spring scale (e.g. this is a spring scale) stretches to be 3cm longer when 80g is placed on it. What is the spring constant of the spring in the scale? 6.4 (What is the period...), A baseball pitcher brings his arm forward during a ptich, rotation the forearm about the elbow. If the velocity of the ball in the pticher's hand is 43.0 m/s and the ball is 0.3m from the elbow joint, what is the angular velocity of the forearm? An ordinary workshop grindstone has a diameter of 15 cm. and rotates at 6500 rev/min. a) Calculate the centripital acceleration at its edge in m/s^2. b) What is the linear speed of a point at its edge? A 68kg student rides on a steadily rotating ferris wheel. At the highest point the normal force from the seat has a magnitude of 550N. a)Does the student feel light or heavy there? b) What is the magnitude of the normal force at the bottom of the ride? c) what is the magnitude of N at the top of the ride if the wheel's speed is doubled? What is the force from the earth on the moon? What is the centripital acceleration of the moon as it goes in a roughly circular orbit around the earth? (Table C3 in the textbook has useful information about the earth and moon)	Nov. 3
Nov. 11	9.1-9.3		Nov. 7
Nov. 14		7.12 (Calculate the force...), 7.21 (In a downhill ski race...), 7.22 (A 5.00x10^5kg subway...), 7.27 (Using energy considerations...), 7.32 (A person in good physical condition...), 7.56 (The swimmer shown in...), and A 75kg cross-country skier is climbing a 2.0deg slope at a constant speed of 3.00m/s and encounters air resistance of 25.0N. a) Find the rate of work done to him (power) by the gravitaional force and by the drag force. b) In light of this how much useful power must propelling him forward (that is, disregard any issues related to the efficiency of the human body)? c) If he continues to push just as hard (same force) after the ground levels out how long will it take to reach 8m/s? (Assume that he adjusts his stance to maintain the same modest drag force he had been experiencing at low speeds and is briefly capable of expending this much higher power).	Nov. 7
Nov. 16	Review		Nov. 7
Nov. 18	Exam 2 (focused on Chapters 4-7)		Nov. 7
Dec. 7		Corrections due	Dec. 2
Dec. 9	Review	Report 2 Due. Chapter 8 8.27 and 8.30, Chapter 9 Problems and Exercises: 9.9, 9.33, 9.37a, Chapter 11 Concept Question 11.8 (How is pressure...) Chapter 13 13.2 (Frost damage...)	Dec. 2