DAY 83
Quiz tomorrow on Momentum and Impulse. Review definitions, concepts, and problems from day 77-83
#Goals: SWBAT...
1. Explore how being at rest affects momentum
2. Use the impulse-momentum equation to solve momentum/impulse problems.
Warm-Up (6min):
Recall: Impulse = F • t & Change in Momentum = m • ∆v
Impulse = Change in Momentum so.... F • t = m • ∆v
Momentum(1min): Is the momentum of a car traveling south different from that of the same car when it travels north at the same speed? Draw a sketch of cars with momentum vectors to support your answer.
Momentum(1min): Which has more momentum, a supertanker tied to a dock or a falling raindrop?
Impulse and Momentum(4min): A 0.174-kg softball is pitched horizontally at 26.0 m/s. The ball moves in the opposite direction at 38.0 m/s after it is hit by the bat.
Draw arrows showing the ball’s momentum before and after the bat hits it?
What is the change in momentum of the ball?
What is the impulse delivered by the bat?
If the bat and softball are in contact for 0.80 ms, what is the average force that the bat exerts on the ball? NOTE: ms means millisecond 1s=1000ms
CLASSWORK:
#083A: Impulse/Change in Momentum Practice Problems
A 240.0-kg snowmobile accelerates, which results in a force being exerted that speeds up the snowmobile from 6.00 m/s to 28.0 m/s over a time interval of 60.0 s.
A. Sketch the event, showing the initial and final situations.
B. What is the snowmobile’s change in momentum? What is the impulse on the snowmobile?
C. What is the magnitude of the average force that is exerted on the snowmobile?
A 2200 kg vehicle traveling at 94 km/h (26 m/s) hits a concrete wall and stops. Suppose a 60.0 kg person is driving the car. The velocity of the person equals that of the car both before and after the crash, and the velocity changes in 0.20 s. Sketch the problem.
A. What is the average force exerted on the person?
B. Some people think that they can stop their bodies from flying forward in a vehicle that is crashing by putting their hands on the dashboard. Divide the force you just calculated using 1lb = 4.448N and find the force you just calculated in pounds.
i. Could you lift something with that weight?
ii. So are you strong enough to stop your body with your arms?
083B: Fish Catch Interactive
Copy, then complete the sentence. Before the collision, only one of two objects is moving. All the momentum of the system resides in a single object before the collision. After the collision, both objects move together at the same _______ as if they were a single ________.
In this activity, you will attempt to develop a mathematical rule for predicting the post-collision velocity for any collision that possesses this characteristic. You will attempt to develop the rule in the form of an equation that states the post-collision velocity (vf) as a function of the pre-collision velocity (vi) and the masses of the moving (m1) and the stationary (m2) objects.
Instructions/Handout Link: https://www.physicsclassroom.com/getattachment/Physics-Interactives/Momentum-and-Collisions/Fish-Catch/Fish-Catch-Exercise/FischCatchActivity.pdf?ext=.pdf
Copy the data table into your notes, then use the interactive to collect data. Once you have all the data, create a rule (equation) relating the qualities described in the paragraph above. Be prepared to share out your rule before the end of class.
Interactive Link: https://www.physicsclassroom.com/Physics-Interactives/Momentum-and-Collisions/Fish-Catch/Fish-Catch-Interactive
Learning at Home (HW)
Complete any incomplete classwork. If you didn't finish the fish catch, we will work on that for 10-15 minutes tomorrow.
Review Day 77-83 for tomorrow's quiz (which will be on Schoology, so login with the Kiosk App tomorrow)
Quiz Monday: Review Momentum & Impulse concepts from Day 80 through 83
#Goals: SWBAT...
1.Calculate Impulse, change in momentum, and force
WARM-UP & HW Check:
Use the impulse-momentum change principle to fill in the blanks in the following rows of the table. As you do, keep these three major truths in mind:
The impulse experienced by an object is the force•time.
The momentum change of an object is the mass•velocity change.
The impulse equals the momentum change.
A. Find the missing info from the data below
B. As you saw in last nights video, cars have crumple zones.
1. If you were in a crash, why would you want your car to partially crumple?
2. Which parts of the car don't you want to crumple? Why?
CLASSWORK:
1. 083A: HW Review
2. 083B: Practice problems:
A. Complete the chart that looks like the warm-up problem. It's about halfway down the page
https://www.physicsclassroom.com/class/momentum/Lesson-1/Momentum-and-Impulse-Connection
B. Complete the Check Your Understanding problems
Learning at Home (HW)
Remind App message me with any questions
- Complete 083B
- 083C: Review the concepts of Impulse and Collisions by looking at how a helmet protects our heads. Take notes, and answer the questions
Edpuzzle Video: https://edpuzzle.com/media/588646c5fc574b496133fff8
- Quiz Monday: Review Momentum & Impulse concepts from Day 80 through 83
Exam Day
Warm-Up check Day 68-82 (15 in total) (starts with 04/23/18). You can show me these today (monday) or tomorrow (tuesday)
CLASSWORK/HOMEWORK
1. #083B: Complete the practice problems using Coulombs Law. Slideshow ---> LINK
Last week we got to slide 8 (example problem #2). Today, practice some more electro-static charge problems by completing example problems 3 and 4, as well as the Skill Builder linked on the last slide. Need extra credit? Just like last time, the third trophy (Putting it all Together) is extra credit.
Need help? I'm here, nutrition and lunch, every day...