Learning Objectives

• Test 2 this week! 
• Ignoble Prize in Rheology
• Launch of Europe Clipper

This weeks test focused on chapter 4 (forces and Newtons laws) and the first part of chapter 5 (friction as a force)

After the test, we discussed the launch of the Europe Clipper satellite along with the stunning ‘catch’ of the SpaceX booster rocket. 

Learning Objectives

Monday was a review of last week’s test. Major point was that every question on the test was one we had seen during class discussion, or was an assigned HW problem or was a solved example from the text book.

Centripetal Forces are reviewed along with the concepts of Period of Motion and Frequency of rotation

New Assignments this week:

• Rocks over your head_fall24

See examples of student notes from this week.

• student notes_10.30a 
• student notes_10.30b
• student notes_10.30c
• student notes_10.30.d

This week circles back to centripetal motion both in general (centripetal forces and acceleration) and with regard to the ‘source of the force’, which can vary from one situation to the next. Of special interest this week, was the case of objects traveling in a vertical plane, being swung by a rope. The example of slowing the rotational velocity down until the rope goes ‘slack’ at the top (Tension just goes to zero) results in the observation that the Force of Gravity is the only force acting on the mass and therefor, must be the Force causing the Centripetal Acceleration.

Learning Objectives

This week married the discussion of centripetal forces in a vertical plane with the concepts of conservation (and transformation) of energy. Specifically, we examined Work and how the motion must be parallel to the forces, Gravitational Potential Energy and Kinetic Energy.

New Assignments: 

• Read sections  7.1 and 7.2 in the On-line text (pages 299-309) Work, Kinetic Energy and the Work Energy theorem.
• Do odd-numbered problems 1-15 on pages 345-346
• solutions_probs 7.1_7.2_Nov01
• Student notes from this week
• notes_banked curves
• notes_banked curves (2)
• notes_rock over head corrections with energy

Demo problem: Work.. A person carries a block up a ramp to a height H, and then allows the block to slide back down (with friction). How much work does the person do, does friction do, and what is the speed of the block at the bottom of the ramp, (and how much heat is produced?).

Discussion: Banked turns and identifying the angle of the bank to keep the car on the road without friction.

Discussion: Reconsidering the ‘rock over your head’ lab which takes into consideration the change in energy from the top of the path to the bottom.

Demo Problem: At what height H, must a block be released so that if it slides down a ramp with a ‘loop’ at the bottom (or radius R), it will stay in contact with the track.

Learning Objectives

New Assignments: 

• Read sections  7.1 and 7.2 in the On-line text (pages 299-309) Work, Kinetic Energy and the Work Energy theorem.
• Do odd-numbered problems 1-15 on pages 345-346
• Meteor Launcher! Students determined the energy stored in a compressed spring and then used that value to predict the launch height of a meteor (a rock? a nut? something small).. when the compressed spring is released. To hand in: A short summary of the physics in action, a data table showing the compression as a function of applied force, a graph showing the slope of the function (the spring constant), a section identifying the available energy when the spring is compressed and a prediction showing how high the projectile ought to attain upon launch. 

Video: History of Car Crashes (history channel)

Discussion: Energy stored in a compressed spring.. with a review of work as a concept, and how the area under the curve of force vs distance represents the total work done and the energy now stored in compressing a spring. 

Demo problem: A person weighing 62 kg is about to jump off of a bridge with a Bungee Rope attached. The rope is 12 meters long. As the jumper falls, she drops a total distance of 30 meters below the bridge before she finally stops. Questions include: Where does she experience the maximum force and what is the value? Where does she experience the maximum acceleration and what is it? You tube Video: A person in a wheel chair enjoys bungee jumping! 

Learning Objectives

New Assignments: 

This week continued with the Meteor Launch Lab, characterizing the spring, launching the mass and comparing the outcomes.