1. Force & Motion

2. SPEED
Describes how fast an object
is moving.

3. Average Speed
distance
Average Speed =
time

4. Velocity
The speed of an object in a certain direction.

5. speed of an object in a certain direction.
(xf-xi)
Velocity
V = t
speed of an object in a certain direction.
V = velocity (meters/second)
d = xf=final distance
xi=initial distance (meters)
Also written as (x2-x1)
t = time (seconds)

6. Velocity
speed of an object in a certain direction.
seconds 3 1 2

7. Speed=? Velocity=? Total time= 4 seconds B 20 meters 12 meters

8. Numerator 5 12
Denominator

9. Acceleration

11. Acceleration is how quickly velocity changes over time.
X L eh ray shun
Speed 3 1 2
Meters/second

12. Acceleration (Vfinal - Vinitial) ___________ A = time
how quickly velocity changes over time.
(Vfinal - Vinitial)
___________
A =
time

13. Acceleration the change in velocity over time.
change in velocity
Acceleration =
time
(v2 – v1 )
________
Acceleration =
Time
V1 = beginning velocity
V2 = ending velocity

14. The graph below relates speed and time of four cars (1, 2, 3, and 4) traveling along a straight highway.
Which two cars move with zero acceleration?
1 and 4
2 and 3
1 and 2
3 and 4

15. Which of these describes the object with the largest acceleration ?
An object with a small change in velocity over a small change in time
An object with a small change in velocity over a large change in time
An object with a large change in velocity over a small change in time
An object with a large change in velocity over a large change in time

16. Scalar a measurement that does NOT contain direction
Scalar a measurement that does NOT contain direction. Egg sample: Speed Vector a measurement that contains direction. Egg sample: Velocity

17. Gravitational Magnetic
Forces of Nature
Gravitational Magnetic

18. Mass and Inertia
The universe
consists of matter
in motion

19. The greater the mass
the harder it is to move.
And . . .
the harder it is to stop moving.

20. the force of a moving body.
momentum
the force of a moving body.
___________
the mass times velocity of an object
p = m • v
Momentum = mass x velocity
(Kgrams) (meters/second)

21. p = m • v Momentum = mass x velocity Higher mass higher momentum
Higher velocity higher momentum
p = m • v

22. Momentum points in the direction of motion.
includes velocity.
So, it has direction.
Momentum points in the direction of motion.

23. Lower mass objects are easier to move . . .and to stop moving.

24. Conservation of momentum
When objects collide, all of the momentum goes somewhere.

25. Conservation of momentum
When objects collide, all of the momentum goes somewhere.

26. When objects collide, all of the momentum goes somewhere.
Conservation of momentum
When objects collide, all of the momentum goes somewhere.

27. When objects collide, all of the momentum goes somewhere.
Conservation of momentum
When objects collide, all of the momentum goes somewhere.

28. When the net force is Zero. -> NO movement
Balanced Forces
When the net force is Zero.
-> NO movement
When the net force is NOT Zero.
-> movement
Unbalanced Forces

29. When all forces are balanced. The net force is Zero.
Static Equilibrium Balanced forces
When all forces are balanced.
The net force is Zero.
There is NO movement.
3 Kg ?
2 Kg

30. 50 N
100 N
50 N
50 N
100 N
50 N

31. Balanced or unbalanced?
Gravity Inertia Friction
Balanced or unbalanced?
Action
Reaction

32. Gravity
balanced UN
BALL
Speed (m/s)
Ground
Time (mSec)

33. Inertia
PUTTER
balanced UN
Speed (m/s)
BALL
Time (mSec)

34. Friction
SKATE
balanced UN
Speed (m/s)
Time (Sec)

35. A car is traveling down a hill
A car is traveling down a hill. Which of the following will affect the amount of energy the car has?
how long the car is
the time of day
how much the car weighs
the color of the car

36. Work

37. {
Work
Distance
W = f • d
Force {
Distance

38. 50 39.2 29.4 19.6 9.8 Projectile Motion 3 1 2 Velocity (m/s) seconds
forward downward 50
39.2
29.4
19.6
9.8
seconds 3 1 2

39. Projectile
Motion
Velocity (m/s)
forward downward 48 47 46 50 49
39.2
29.4
19.6
9.8
seconds 3 1 2

40. Simple Machines Pulley Wheel & Axle Lever Inclined plane Screw Wedge
Gear

41. ALL Simple Machines work the same way
Force
Distance x

42. Lever action
2 meters
1 meter
Force= ?
Force=13 N

43. Mechanical
Advantage= final distance
starting distance
9 meters
3 meters

44. Mechanical
Advantage= distance
distance
8 meters
2 meters

45. calculating mechanical Advantage
A 200 pound man lifts a rock weighing 800 pounds by standing on the end of a lever. How much mechanical advantage did the lever provide ?
            
calculating
mechanical
Advantage
M.A. = 800 Kg/200 Kg = 4

46. Newton’s Law of Gravitation
Gravitation is a force of attraction between any two objects with mass.
Mass of A
Mass of B
Distance between Objects 46

47. If you wuz ‘n a
Merry-go-round
& yuz let go,
Which wayz wud yu go?

48. The inward force on a spinning object, that stops it from going in
Centripetal force
The inward force
on a spinning object,
that stops it
from going in
a straight line.
Perpendicular

49. Centripetal: “towards the center”.
Radial: Along the radius of a circle.
Centripetal is often used interchangeably with radial.

50. Centripetal force
The
inward force
on a
Spinning
object.

51. An object moving in a circle is experiencing acceleration
An object moving in a circle is experiencing acceleration. Even if moving around the perimeter of the circle with a constant speed, there is still a change in velocity due to a change of direction and subsequently an acceleration. This acceleration is directed TOWARDS THE CENTER of the circle.
Objects will tend to naturally travel in straight lines; an unbalanced force is required to cause it to turn.
The presence of THE UNBALANCED FORCE is required for objects to move in circles.
Gravity
Inertia 51

52. Newton’s Laws of Motion Review
Law #1: An object will move forever in a straight line at the same speed unless some external force changes its direction or speed.
Law #2: The acceleration of an object multiplied by the mass of the object is equal to the net force acting on the object.
Law #3: For every action, there is always an equal and opposite reaction. 52

53. Newton's first law of motion - the law of inertia states that….
"... objects in motion tend to stay in motion with the same speed and the same direction unless acted upon by an unbalanced force."
Objects travels in a straight line

54. 1st Law
Once airborne, unless acted on by an unbalanced force (gravity and air – fluid friction), it would never stop!

55. 1st Law
Unless acted upon by an unbalanced force, this golf ball would sit on the tee forever.

56. It’s a force we sometimes cannot see – friction.
Why then, do we observe every day objects in motion slowing down and becoming motionless seemingly without an outside force?
It’s a force we sometimes cannot see – friction.

57. Objects on earth, unlike the frictionless space the moon travels through, are under the influence of friction.

58. Friction! There are four main types of friction:
What is this unbalanced force that acts on an object in motion?
Friction!
There are four main types of friction:
Sliding friction: ice skating
Rolling friction: bowling
Fluid friction (air or liquid): air or water resistance
Static friction: initial friction when moving an object

59. Friction  
the resistive force that occurs when two surfaces travel past each other.
causes physical deformation
generates heat

60. Friction  
the resistive force that occurs when two surfaces contact each other.  

61. Oliver the dog doesn't want to walk in the rain
Oliver the dog doesn't want to walk in the rain. He can make his owner pull harder on the leash to get him out the door by sitting on the vinyl floor. sitting on the tile floor. sitting on the carpeted floor. sitting on the wood floor.

62. Pauline needs to measure the sliding friction of a brick
Pauline needs to measure the sliding friction of a brick. How should she go about doing this?
attach the brick to a string and then to a spring scale and read the force needed to quickly lift the brick off the ground
drag the brick by a string attached to a spring scale so that it gradually speeds up
drag the brick by a string attached to a spring scale along the surface of a table at a constant speed and read the force
hang the brick from a string attached to a spring scale and read the force

63. Sliding friction-the drag force created when the surface of one object slides across the surface of another object.
Sliding Friction Lab
Object
Surface
force (Newstons)

64. terminal velocity gravity will accelerate an object until air resistance (friction) does not allow it to go any faster.
gravity
air resistance

65. In the absence of air resistance, which of these objects will fall at the fastest rate when dropped?
the ball with a mass of 75 kg
the ball with a mass of 25 kg
the ball with a mass of 10 kg
They all fall at the same rate.

66. Newtons’s 1st Law and You
Don’t let this be you. Wear seat belts.
Because of inertia, objects (including you) resist changes in their motion. When the car going 80 km/hour is stopped by the brick wall, your body keeps moving at 80 m/hour.

67. 2nd Law
The net force of an object is equal to the product of its mass and acceleration, or F=ma.

68. f = m•a NEWTON’s 2nd Law of Motion : f = net force (newtons)
f = m•a
force = mass • acceleration
f = net force (newtons)
m = mass (Kilograms)
a = acceleration (meters/second2)

69. 2nd Law
When mass is in kilograms and acceleration is in m/s/s, the unit of force is in newtons (N).
One newton is equal to the force required to accelerate one kilogram of mass at one meter/second/second.

70. 2nd Law (F = m x a)
How much force is needed to accelerate a 1400 kilogram car 2 meters per second/per second?
Write the formula
F = m x a
Fill in given numbers and units
F = 1400 kg x 2 meters per second/second
Solve for the unknown
2800 kg-meters/second/second or 2800 N

71. Pressure is the amount of force exerted over a certain area.
Pressure = Force
Area

72. Pressure = Force (newtons)
Area (m2)
1 Pascal = 1 Newton/meter2

73. Net force is the total amount of Force (minus the forces that cancel each other out).
Force of gravity
Force of muscles
Net force

74. If mass remains constant, doubling the acceleration, doubles the force
If mass remains constant, doubling the acceleration, doubles the force. If force remains constant, doubling the mass, halves the acceleration.

75. Newton’s 2nd Law proves that different masses accelerate to the earth at the same rate, but with different forces.
We know that objects with different masses accelerate to the ground at the same rate.
However, because of the 2nd Law we know that they don’t hit the ground with the same force.
F = ma
98 N = 10 kg x 9.8 m/s/s
F = ma
9.8 N = 1 kg x 9.8 m/s/s

76. Check Your Understanding
1. What acceleration will result when a 12 N net force applied to a 3 kg object? A 6 kg object?
2. A net force of 16 N causes a mass to accelerate at a rate of 5 m/s2. Determine the mass.
3. How much force is needed to accelerate a 66 kg skier 1 m/sec/sec?
4. What is the force on a 1000 kg elevator that is falling freely at 9.8 m/sec/sec?

77. Check Your Understanding
1. What acceleration will result when a 12 N net force applied to a 3 kg object?
12 N = 3 kg x 4 m/s/s
2. A net force of 16 N causes a mass to accelerate at a rate of 5 m/s2. Determine the mass.
16 N = 3.2 kg x 5 m/s/s
3. How much force is needed to accelerate a 66 kg skier 1 m/sec/sec?
66 kg-m/sec/sec or 66 N
4. What is the force on a 1000 kg elevator that is falling freely at 9.8 m/sec/sec?
 9800 kg-m/sec/sec or 9800 N

79. Conservation of energy
NEWTON’s
3rd Law of Motion:
Conservation of energy
For every action there is
an equal and opposite reaction.

80. NEWTON’s 3rd Law of Motion: For every action, there is
For every action, there is
an equal and opposite reaction.

82. 3rd Law
According to Newton, whenever objects A and B interact with each other, they exert forces upon each other. When you sit in your chair, your body exerts a downward force on the chair and the chair exerts an upward force on your body.

83. 3rd Law
There are two forces resulting from this interaction - a force on the chair and a force on your body. These two forces are called action and reaction forces.

84. Newton’s 3rd Law in Nature
Consider the propulsion of a fish through the water. A fish uses its fins to push water backwards. In turn, the water reacts by pushing the fish forwards, propelling the fish through the water.
The size of the force on the water equals the size of the force on the fish; the direction of the force on the water (backwards) is opposite the direction of the force on the fish (forwards).

85. 3rd Law
Flying gracefully through the air, birds depend on Newton’s third law of motion. As the birds push down on the air with their wings, the air pushes their wings up and gives them lift.

86. Consider the flying motion of birds. A bird flies by use of its wings
Consider the flying motion of birds. A bird flies by use of its wings. The wings of a bird push air downwards. In turn, the air reacts by pushing the bird upwards.
The size of the force on the air equals the size of the force on the bird; the direction of the force on the air (downwards) is opposite the direction of the force on the bird (upwards).
Action-reaction force pairs make it possible for birds to fly.

87. Other examples of Newton’s Third Law
The baseball forces the bat to the left (an action); the bat forces the ball to the right (the reaction).

88. 3rd Law
Consider the motion of a car on the way to school. A car is equipped with wheels which spin backwards. As the wheels spin backwards, they grip the road and push the road backwards.

89. 3rd Law
The reaction of a rocket is an application of the third law of motion. Various fuels are burned in the engine, producing hot gases.
The hot gases push against the inside tube of the rocket and escape out the bottom of the tube. As the gases move downward, the rocket moves in the opposite direction.

90. Gravitational force
Gravity

91. Gravitational force
Gravity

92. Gravitational force
INCREASES with Mass
DECREASES with Distance

93. Elliptical Path of Earth
The planets move in elliptical orbits (not circular).
The Sun is at one focus of the ellipse.
Because the orbit is elliptical, a planet’s distance from the Sun will change throughout its orbit.
Earth
Sun - Focus
Secondary - Focus

94. Ellipses and Eccentricity
e = eccentricity characterizes how squished (flattened) the circle is.
Perfectly round ellipse is a circle and has eccentricity = e = 0
Very flattened ellipse has eccentricity = e = 0.99
Eccentric orbit = elliptical orbit = orbit is an ellipse with high eccentricity.

95. Eccentricity

96. Kepler’s Laws of Planetary Motion
The closer a planet comes to the Sun, the more rapidly it moves.
Known as the “equal area” law.
While Kepler thought a planet would not have a constant speed while in orbit, he wasn’t able to explain why. 96

97. Kepler’s Second Law of Speed Change
Area B
Area A .
Planet moves faster to cover a greater distance
Planet moves more slowly covering a lesser distance B C

98. Satellites stay in place as they orbit because of . . .
the repeated firing of rocket boosters.
the gravitational pull of Earth.
a narrow path through the vacuum of space.
solar panels generating energy to hold them in place

99. Create a Cartoon
Today you are making a cartoon strip. Your cartoon strip should be about a super hero who uses the power of forces to save people. Your cartoon should have eight sections that include examples of:
3 Contact Forces
3 Non-Contact Forces
Labels for each force
Color
Due Tuesday 1/30

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