Download Test 1

Physical Science
PHS 101
Test 1
Beiser Chapter 1, 2, 3, 5
452 South Anderson Road
Rock Hill, SC 29730
www.yorktech.com
Scientific Method
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Physics - Motion & Energy
Physics - Electricity, Magnetism & Optics
Chemistry
Meteorology
Geology
Astronomy
Tiger got to hunt,
Bird got to fly;
Man got to sit and
wonder, "Why, why, why?"
Tiger got to sleep,
Bird got to land;
Man got to tell
himself he understand.
- Kurt Vonnegut
Chapter 1
Physical Quantities
Beiser p.1
Scientific Notation
Good for very big or very small numbers.
300,000,000
= 3 x 100,000,000
= 3 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10
= 3 x 108
0.0000052
= 5.2 ÷ 1,000,000
= 5.2 x 10-6
Beiser p.1
Unit Conversions
Since 3 ft = 1 yd
30 ft  ____ yds
 1 yd 
  30  3 yds  10 yds
30 ft 
 3 ft 
3.72 yds  ____ ft
 3ft 
3.72 yds 
  3.72  3ft  11.16ft
 1yd 
Beiser p.2
Unit Conversions
Since 5280 ft = 1 mi and 1 m = 3.28 ft
3.1 mi  ____ m
 5280 ft  1 m 

  3.1* 5280  3.28  4990 m
3.1 mi 
 1 mi  3.28 ft 
50000 m  ____ mi
 3.28ft  1mi 
50000 m 

  50000*3.28  5280  31.1 mi
 1m  5280 ft 
Beiser p.2
Metric Arrow
1000m
100m
10m
1m
.1m
.01m
.001m
kilo
hecto
deka
meters
deci
centi
milli
km
hm
dkm
m
dm
cm
mm
king
henry
died
don’t
call
me
3.72 dkm = 3720 cm
1.5 m = 1500 mm
1200 cm = 12 m
1.5 m = .015 hm
1655 dm = .1655 km
Beiser p.2
Vector Addition
Beiser p.3
1.27
Beiser p.9
Chapter 2
Motion in a Straight Line
Beiser p.10
Velocity
distance
velocity 
time
s
v
t
s  vt
s
t
v
Beiser p.10
Velocity Examples
1) If a person walks 15
miles in 3 hours, what is
her average velocity?
2) If a car travels at a
velocity of 2 m/s for 30
seconds, how far did it
go?
3) If I travel 175 miles at 70
miles per hour, how long
will it take?
4) If a plane travels north at
120 mph for 3 hr and then
turns and flies west at
100 mph for 2 hr, how far
away from its starting
point is it?
s 15 mi
1) v  
 5 mi / hr
t
3hr
 m
2) s  vt   2   30s   60 m
 s
s 175 mi
3) t  
 2.5 hr
v 70 mi
hr
4) s  3602  1002
 139600
 373.6 mi
Beiser p.10
Acceleration
A change in speed in time
v  vO
a
definition of accelerati on
t
1 2
s  v O t  at distance an accelerati ng object goes
2
v  v O  at
final velocity of an accelerati ng object
acceleration due to gravity = g = 9.8 m/s2 = 32 ft/s2
Beiser p.10
Acceleration Examples
v  v0
5) If my car is stopped
5) a 
at a light and then
t
speeds up to 4 m/s in
40m/s
2

 2m/s
2 s, find the
2s
acceleration.
6) If I'm traveling 6 m/s 6) a  v  v 0
t
and step on the
brakes to slow down
26m/s
2



.
5
m
/
s
to 2 m/s in 8 s, find
8s
the acceleration.
Beiser p.10
Freefall
If you drop a
rock from
the top of a
building..
after 1, 2,3
and 4
seconds
7) how fast will
it be
moving?
8) how far will
it have
fallen?
Time
(s)
1s
Velocity Distance
(m/s)
(m)
9.8 m/s
4.9 m
2s
19.6
m/s
19.6 m
3s
29.4
m/s
44.1 m
4s
39.2
m/s
784 m
7) v  v o  at
 0  9.8 m / s t 
1 2
8) s  v o t  at
2
1
2 2
 (0)( t )  (9.8 m / s ) t
2
 4.9 t 2
(ignore air
resistance)
Beiser p.11
Chapter 3
The Laws of Motion
Beiser p.18
Newton’s First Law
• 1st Law – A body at rest will stay at rest & a
body in motion will stay in linear motion at
constant velocity until a net force acts on
it.
V
Beiser p.18
Newton’s Second Law
• 2nd Law – A net force on a mass causes an
acceleration.
F = ma
a
F
m
Beiser p.18
Newton’s Third Law
• 3rd Law – Every action (force) has an
equal but opposite reaction.
Table pushes up on
box.
Weight of box pushes
down on table.
Beiser p.19
Weight & Mass
• Mass is how much “stuff” something has.
• Weight is how much gravity pulls on the “stuff”.
Object on Earth
Metric
British
Same object in space
Gravity pulls on mass.
No gravity to pull on mass.
Object has mass & weight.
Object has same mass, but no weight.
Mass
Kg
slug
Weight
Newton
Pound
w  mg
w
m
g
Beiser p.19
Chapter 5
Energy
Beiser p.35
Work
Using a force to move an object:
W = Fs = mgs
F is force,
s is distance
m is mass
g is gravity
Measured in kg m2/s2 = J (metric) or ft lbs (English)
Ex: How much work does it take to lift a 200 kg box 3 m into
the air?
W = mgh = (200 kg)(9.8 m/s2)(3 m) = 5880 J
Beiser p.35
Power
The rate of work or how fast work gets done
W
P
t
Ex: How much power does it take to lift a 200 kg
box 3 m into the air in 30s,
w mgs (200 kg)(9.8 m / s 2 )(3m)
P 

 196 W
t
t
30s
Beiser p.35
Power Lifting Box
Beiser p.40
Lifting Box English Units
Beiser p.40
Kinetic Energy
The energy of a moving object
1
2
KE  m v
2
(m is mass of the object, v is the velocity)
Ex: Calculate the kinetic energy of a car that has a
mass of 1500 kg moving at a speed of 5 m/s.
KE = ½ m v2 = ½ (1500 kg)(5 m/s)2 =18,750 J
Beiser p.36
Potential Energy
The energy an object develops by being raised
to a height
PE = mgh
(m is mass, g = 9.8 m/s, h is height)
EX: Calculate the potential energy of a book
that has a mass of 5 kg that is 2 m above the
ground.
PE = mgh = (5 kg)(9.8 m/s2)(2 m) = 98 J
Beiser p.36
PE Example
Beiser p.36
Conservation of Energy
The total energy of a system cannot change
unless energy is taken from or added to
the system. At any two points, 1 and 2
PE1 + KE1 = PE2 + KE2
Beiser p.36
Cons. Of Energy
Beiser p.36
Cons.of Energy Ex.
Beiser p.36
Energy Summary
Name
Symbol
Description
Formula
Units
Kinetic Energy
KE
Energy of
moving object
KE = ½ m v2
Joules or
Ft lbs
Potential
Energy
PE
Energy of
raised object
PE = mgh
Joules or
Ft lbs
Work
W
Force moving
an object
W = Fd
Joules or
Ft lbs
Energy is
constant
W = PE = KE
Joules or
Ft lbs
Speed of work
P=W/t
Watts or
Ft lbs / s or hp
Conservation of
energy
Power
P
Test 1 Equations
2.24
Beiser p.16
2.38
Beiser p.16
3.8
Beiser p.21
3.29
Beiser p.24
3.35
Beiser p.24
3.39
Beiser p.25