Newton’s 2 nd Law of Motion 11/25/13 – 11/26/13 Lesson1 Newton’s 2 nd Law of Motion WB: p.76, review p.77-80,

Date: 11/25/13Objective: I can read and understand procedures to perform an activity on Newton’s second law of motion Bell Ringer: If a roller coaster’s first hill is 40 m tall, which of the following heights is a possibility for the second hill? Explain your answer 30m, 40m, 50m, or 60m

Date: 11/25/12Objective: I can read and understand procedures to perform an activity on Newton’s second law of motion Open work book to page 73 Group read Equipment Set Up

Date: 11/25/13Objective: I can read and understand procedures to perform an activity on Newton’s second law of motion Open work book to page Set up data table Net force of hanging mass.02kg(20g) x 9.8N/kg=.196N ItemMass (kg)Acceleration Run #1 Total mass of cart (100g) Run #2 Total mass of cart plus 100g.1 kg Run #3 Total mass of cart plus 200g.2 kg Run #4 Total mass of cart plus 300g.3 kg

Date: 11/26/12Objective: I can read and understand procedures to perform an activity on Newton’s second law of motion Open work book to page Set up data table

Date: 11/26/13Objective: I can read and understand procedures to perform an activity on Newton’s second law of motion work book to page Perform activity Person #1 supplies-set up, take down, and care of Person #2 operates the glx Person #3 records data Person #4 manages and protects car

Date: 12/1/13Objective: I can determine what happens to an object, when a net force is applied to it. I can also determine what happens to the motion of an object as the mass changes and the net force stays the same. Bell Ringer: If the object to the right has a gravitational force of 800N pulling it down (towards __ ____ _ __ ___) and air pushing up with a force of 600 N. What is the net force acting on the object? Explain what will happen to the object.

What is the net force? A B C With your group, determine the net force of each of the objects above

What is our data? ItemMass (kg) Acceleration M/S/S Run #1 Total mass of cart (100g) Run #2 Total mass of cart plus 100g.1 kg Run #3 Total mass of cart plus 200g.2 kg Run #4 Total mass of cart plus 300g.3 kg

What can we determine from our data? Workbook p. 76 What is a claim? Discuss your answer with your shoulder partner a statement which is either true or false that is trying to be proven.

What can we determine from our data? Workbook p. 76 Complete Support for conclusion Claim based on evidence 1.When a net force acts on a object _____ ____________________________________ Discuss the answer with your face partner Discuss your answer with your shoulder partner

What can we determine from our data? Workbook p. 76 Complete Support for conclusion Claim based on evidence 2. When the mass of the object is increased and the magnitude of the force on the object remains constant its acceleration ______________ ____________________________________ Discuss the answer with your face partner Discuss your answer with your shoulder partner

What can we determine from our data? Workbook p. 76 Complete Support for conclusion Evidence (observations, use data as evidence) 1.When a net force____________________ acts on a object,____________________ the object accelerates.____________________ Discuss the answer with your face partner Discuss your answer with your shoulder partner

What can we determine from our data? Workbook p. 76 Complete Support for conclusion Evidence (observations, use data as evidence) 2. When the mass of the object _____________________________ is increased and the magnitude_____________________________ of the force on the object_____________________________ Remains constant its acceleration _____________________________ decreased Discuss the answer with your face partner Discuss your answer with your shoulder partner

What can we determine from our data? Workbook p. 76 Conclusion Combine your claim and evidence together to create your conclusion. My claim is________ because Evidence with reason Create your conclusion independently Discuss your answer with your shoulder partner

Look at this figure. The mass of the bowling ball does not change, but the mass of the puppy does. How? Where does the matter come from? Can the mass of the bowling ball ever change?

Place these 5 items in the order they would be the most attracted to the Earth due to gravity. Explain why you picked your order. House fly Tennis ball Elephant Bowling ball peanut

Exit Question What would happen to your mass and to your weight if you went to the moon? Explain how you arrived at your answer.

Example of a conservative system: The simple pendulum. Suppose we release a mass m from rest a distance h 1 above its lowest possible point. – What is the maximum speed of the mass and where does this happen ? – To what height h 2 does it rise on the other side ? v h1h1 h2h2 m

Example: The simple pendulum. y y= 0 y=h 1 – What is the maximum speed of the mass and where does this happen ? E = K + U = constant and so K is maximum when U is a minimum.

Example: The simple pendulum. v h1h1 y y=h 1 y=0 – What is the maximum speed of the mass and where does this happen ? E = K + U = constant and so K is maximum when U is a minimum E = mgh 1 at top E = mgh 1 = ½ mv 2 at bottom of the swing

Example: The simple pendulum. y y=h 1 =h 2 y=0 To what height h 2 does it rise on the other side? E = K + U = constant and so when U is maximum again (when K = 0) it will be at its highest point. E = mgh 1 = mgh 2 or h 1 = h 2

Example The Loop-the-Loop … again l To complete the loop the loop, how high do we have to let the release the car? l Condition for completing the loop the loop: Circular motion at the top of the loop (a c = v 2 / R) l Exploit the fact that E = U + K = constant ! (frictionless) (A) 2R (B) 3R(C) 5/2 R(D) 2 3/2 R h ? R Car has mass m Recall that “g” is the source of the centripetal acceleration and N just goes to zero is the limiting case. Also recall the minimum speed at the top is U b =mgh U=mg2R y=0 U=0

Example The Loop-the-Loop … again l Use E = K + U = constant l mgh + 0 = mg 2R + ½ mv 2 mgh = mg 2R + ½ mgR = 5/2 mgR h = 5/2 R R h ?

An experiment Two blocks are connected on the table as shown. The table has a kinetic friction coefficient of  k. The masses start at rest and m 1 falls a distance d. How fast is m 2 going? T m1m1 m2m2 m2gm2g N m1gm1g T fkfk Mass 1  F y = m 1 a y = T – m 1 g Mass 2  F x = m 2 a x = -T + f k = -T +  k N  F y = 0 = N – m 2 g | a y | = | a y | = a =(  k m 2 - m 1 ) / (m 1 + m 2 ) 2ad = v 2 =2 (  k m 2 - m 1 ) g / (m 1 + m 2 )  K= -  k m 2 gd – Td + Td + m 1 gd = ½ m 1 v 2 + ½ m 2 v 2 v 2 =2 (  k m 2 - m 1 ) g / (m 1 + m 2 )