newton’s first law of motion 11/18/13 – 11/22/13 11/18 weight vs mass textbook p 392-393 11/19...
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Newton’s First Law of Motion11/18/13 – 11/22/13
11/18 Weight vs Mass Textbook p 392-393
11/19 Newton’s 1st Law of Motion Workbook p 65-68
11/20 Newton’s 1st Law of Motion Workbook p. 69-72
11/21 Newton’s 1st Law of Motion WB p. 73-7611/22 Quiz
Date: Objective: I can distinguish between mass and weight. I can also calculate weight in Newtons (N)
Bell Ringer:1. As the roller coaster travels from point A to B, how do its potential and kinetic energies change? 2. As the roller coaster travels from point D to E, how do its potential and kinetic energies change?
A
B
C
D
E
Date: Objective: I can distinguish between mass and weight. I can also calculate weight in Newtons (N)
Activity Titled : Textbook p. 392Answer Investigate Part A questions 1-5 in your
NotebookAnswer questions with your shoulder partner. Both
partners must write their answers
DEFINITIONS
Mass- the amount of matter an object has.
Matter- something that has mass and takes up space.
Weight- is the amount of mass of an object, it is dependent upon gravity.
1 pound (lbs)= .45 kilogram (kg)
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 ballpeanut
Exit QuestionWhat would happen to your mass and to your weight if you went to the moon?
Explain how you arrived at your answer.
Singing on the moonhttps://www.youtube.com/watch?v=FMnzi8iFnG8Lunar Olympicshttps://www.youtube.com/watch?v=16D0hmLt-S0
Date: Objective: I can investigate Newton’s first law of motion
Bell Ringer:1.What would happen to your mass and to
your weight if you went to the moon? Explain how you arrived at your answer.
2.Calculate the weight of a 50kg ball?Fw=mg
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 ballpeanut
Date: Objective: I can understand Newton’s first law of motion and apply the concept to my daily life
Bell Ringer:Based on our activityYesterday, if the rollerCoaster starts at point BWhat point will the cart Reach? D or E or FExplain why
Example of a conservative system: The simple pendulum.
• Suppose we release a mass m from rest a distance h1 above its lowest possible point.– What is the maximum speed of the mass and where does
this happen ?– To what height h2 does it rise on the other side ?
v
h1 h2
m
Example: The simple pendulum.
y
y=0
y=h1
– 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
h1
y
y=h1
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 = mgh1 at top
E = mgh1 = ½ mv2 at bottom of the swing
Example: The simple pendulum.
y
y=h1=h2
y=0
To what height h2 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 = mgh1 = mgh2 or h1 = h2
Potential Energy, Energy Transfer and Path• A ball of mass m, initially at rest, is released and follows three
difference paths. All surfaces are frictionless 1. The ball is dropped2. The ball slides down a straight incline3. The ball slides down a curved inclineAfter traveling a vertical distance h, how do the three speeds compare?
(A) 1 > 2 > 3 (B) 3 > 2 > 1 (C) 3 = 2 = 1 (D) Can’t tell
h
1 32
An experimentTwo blocks are connected on the table as shown. The tablehas a kinetic friction coefficient of k. The masses start at
rest and m1 falls a distance d. How fast is m2 going?
T
m1
m2
m2g
N
m1g
T
fk
Mass 1 Fy = m1ay = T – m1g
Mass 2 Fx = m2ax = -T + fk = -T + k N
Fy = 0 = N – m2g
| ay | = | ay | = a =(km2 - m1) / (m1 + m2)
2ad = v2 =2(km2 - m1) g / (m1 + m2)
K= - km2gd – Td + Td + m1gd = ½ m1v2+ ½ m2v2
v2 =2(km2 - m1) g / (m1 + m2)