Example of a Newton
One newton (N) is the force it takes to change
the speed of a 1 kg mass by 1 m/s in 1 second.
Time
1N
Time
1 kg
2 m/s
1 m/s
1N
1 kg
Equation for Newton’s Second Law
Acceleration
(m/s2)
F
a=
m
Force (N)
Mass (kg)
More mass
Mass
Mass
F
m
F
m
Less
acceleration
a=
Speed increases
faster
More
acceleration
a=
Speed increases
Acceleration
Newton’s Second Law
Force
More force
Force
m
F
Speed increases
slower
a
=
Object in Free Fall
Start
0 m/s
After 1 second
9.8 m/s
After 2 seconds
19.6 m/s
After 3 seconds
29.4 m/s
Newton’s Third Law
Reaction force
More
acceleration
Action force
Less
acceleration
Converting Energy
+- 120 volts
CH4 + 2O2
2H2O + CO2 + energy
Chemical energy
+- 120 volts
0 volts
+- 120 volts
0 volts
0 volts
Safety ground (0 volts)
Electrical energy
Hot
steam
Heat energy
Mechanical energy
Some Important Variables in the System
g
Time
Mass
on
ti
Posi
ed
Spe
Angle
Systems and Variables
System includes:
car, ramp, angle,
speed, time, mass
tion
Posi
ed
Spe
Angle
Not included:
color, light, window,
floor or friction
(or anything else)
Work
Work (joules) Force (newtons)
W = Fd
1N
1 meter
Distance (meters)
in the direction of the force
Block
Lifting the 1 newton
block 1 meter requires
1 joule of work.
Power
Power (watts)
Michael
seconds
P= W
t
100 N
Work (joules)
Time (seconds)
Jim
2m
100 N
seconds
Michael and Jim do the same amount of work
but do not have the same power.
2m
Power Example
Start
Work
100 N
Power
10 m
10 seconds
60 seconds
1,000 J
100 W
1,000 J
16.7 W
Power = Amount of work done
time
Energy Flow
Mechanical Advantage of a Lever
Mechanical
advantage
Li
MAlever =
Lo
Input
arm
Li
Fulcrum
Length of
input arm (m)
Length of
output arm (m)
Output
arm
Lo
Mechanical Advantage
Mechanical
advantage
Fo
MA =
Fi
Output force (N)
Input force (N)
Output force
Input force
200 kg
Input
force
Output
force
A small input force can create a large output force
for simple machines with a mechanical advantage greater than one.
The Three Classes of Levers
1st Class
Output force
Input force
Input force
Output
force fulcrum
Input
force
2nd Class
Output force
Input force
fulcrum
Output
force
3rd Class
Input force
Input
force
Output force
fulcrum
Output
force
Earth
Image: NASA
Forming a Planetary System
Jupiter
NASA photo
Mars
ESA photo
Mercury
Image from radar maps, NASA
Planet Overview
Property
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Pluto
Diameter (km)
4,878
12,102
12,756
6,794
142,796
120,660
51,200
49,500
2,200
3.3 × 1023
4.9 × 1024
6.0 × 1024
6.4 × 1023
1.9 × 1027
5.7 × 1026
8.7 × 1025 1.0 × 1026
1.3 × 1022
5.44
5.25
5.52
3.91
1.31
0.69
1.21
1.67
1.75
58
108
150
228
778
1430
2870
4500
5910
Major moons (#)
0
0
1
2
39
30
21
8
1
Strength
`of gravity (N/kg)
3.7
8.9
9.8
3.7
23.1
9.0
8.7
11.0
0.6
Surface
temperature (°C)
-170 to
+400
+450 to
+480
-88 to
+48
-89 to
-31
-108
-139
-197
-201
-223
59
243
1
1.03
0.41
0.43
0.72
0.67
6.4
0.24
0.62
1
1.9
12
29
84
165
249
47.89
35.04
29.80
24.14
13.06
9.64
6.80
5.43
4.74
Mass (kg)
Density
(g/cm3)
Average
distance
from sun
(million km)
Rotation period
(Earth days)
Revolution
period
(Earth years)
Orbital speed
(km/sec)
Planet Size Relative to the Sun
Pluto
Pluto
Image courtesy NASA/JPL-Caltech
Saturn
NASA photo
The Solar System
Uranus and Neptune
Uranus
Neptune
Images: NASA Jet Propulsion Labratory
Venus
Image: NASA
Evolution of a Sun-like Star
Luminosity
Bright
Pluto
Dim
25,000 10,000
6,000
Temperature (ºC)
3,000
Stars, Color and Temperature
Ultraviolet
Light output
{
Infrared
Visible light
Color
Sun Anatomy
Types of Galaxies
Spiral
Barred spiral
Lenticular
Elliptical