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Physical Science Review 1

Terms in this set (29)

Acceleration of gravity and free fall motion
Acceleration of gravity: g = 9.8 m/s^2

Free fall motion: v2 = v1 + (g) (t)
What is the Scientific Method?
A continuing process
Difference between Physical Science and Life Science
Physical Science - non-living (examples: physics, chemistry, geology)

Life Science - living (examples: biology, zoology)
Names of eight planets in the solar system
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
Ptolemaic System and Copernican System
Ptolemaic System: everything revolved around the Earth, believed Earth was center of universe

Copernican System: modern system, the Earth rotates once a day on its axis, the Moon circles the Earth, and the other plants circle the Sun, Earth takes 365 to circle the Sun, no constant distance from Sun to planet
Kepler's first and second laws
Kepler's First Law: The orbits of planets around the Sun are ellipses, distances changes

Kepler's Second Law: A planet moves so that its radius vector sweeps out equal area in equal time, speed changes
Law of Gravity (who discovered this law?)
Isaac Newton

There is an attracting force between any two bodies everywhere in universe
The tides (reason)
Gravitational forces between the Earth and the Moon (mostly) and the Sun
How did scientist find the Neptune?
By law of gravity, then by telescope in 1846
Vector (magnitude and direction) and scalar (magnitude only)
Vector examples: Velocity, force, and acceleration

Scalar examples: Mass, time, and speed
Speed, velocity, and acceleration (formulas and units)
Speed: v = d / t
Unit of time

Acceleration: a = (v2 - v1) / t
Unit of m/s^2
Distance under constant acceleration (formulas and units)
d = v1 (t) + (1/2) (a) (t^2)
Unit of meter
The two facts of a projectile motion
1. Horizontal motion and vertical motion are independent

2. Maximum range at 45 degrees of initial angle
Mass, force, and weight (units)
Mass: Unit of kilogram

Force: Unit of Newton

Weight: Unit of Newton
Newton's 1st law, 2nd law, and 3rd law of motion
1st: An object will keep rest or a "straight line" motion without interacting

2nd: Acceleration is proportional to the force and inversely proportional to the mass

3rd: For every action force, there is an equal but opposite reaction force
Centripetal force (formulas and units)
Fc = ((m) (v^2)) / r
Unit of newtons
Gravitational force (formulas and units)
F = ((G) (m1) (m2)) / (R^2)
Unit of newtons
The speed of a car changes from 12 m/s to 30 m/s in 4.0 seconds. Find the acceleration. (Answer: a=4.5m/s^2)
a = (v2 - v1) / t
a = (30-12) / 4
a = 4.5

a = 4.5 m/s^2
The initial speed of a car is 5.0 m/s. If the acceleration is 2.5 m/s^2, find its speed after 6.0 seconds. (Answer: v2=20m/s)
a = (v2 - v1) / t
2.5 = (v2-5) / 6
15 = (v2-5)
20 = v2

v2 = 20 m/s
A ball is dropped at 2.0 m/s of initial speed. Find the final after 3.5 seconds. (Answer: v2=36.3m/s)
v2 = v1 + (g) (t)
v2 = 2 + 9.8 (3.5)
v2 = 2 + 34.3
v2 = 36.3

v2 = 36.3 m/s
The acceleration of a car is 3.0 m/s^2. If the initial speed is 2.0 m/s, after the car traveled 5.0 seconds, find (a) the final speed and (b) the traveling distance. (Answer: v2=17m/s, d=4.7m)
a = (v2 - v1) / t
3 = (v2-2) / 5
15 = v2 - 2
17 = v2

d = (v1) (t) + (1/2) (a) (t^2)
d = 2 (5) + (1/2) (3) (5^2)
d = 10 + (1/2) (3) (25)
d = 10 + (1/2) (75)
d = 10 + 37.5
d = 47.5

v2 = 17 m/s
d = 47.5 m
A ball is dropped vertically with initial speed of 0.8 m/s. Find the time when the final speed equals 40 m/s. (Answer: t=40s)
v2 = v1 + (g) (t)
40 = 0.8 + 9.8t
39.2 = 9.8t
4 = t

t = 4.0 s
A 1200 kg car speeds up from 30.0 m/s to 60 m/s in 2.5 seconds. Find (a) the acceleration and (b) the average force acting upon it. (Answer: a=12m/s^2, F=14400N)
a = (v2 -v1) / t
a = (60-30) / 2.5
a = 30 / 2.5
a = 12

F = (m) (a)
F = 1200 (12)
F = 14400

a - 12 m/s^2
F = 14400 N
If the speed of a 2,000 kg truck is 22.0 m/s, what is the centripetal force when the car rounds a turn of radius 350 m? (Answer: Fc=2766N)
Fc = ((m) (v^2)) / r
Fc = (2,000(22^2)) / 350
Fc = (2,000(484)) / 350
Fc = (96,800) / 350
Fc = 2.765

Fc = 2.765 N
When a 500 kg car turns around a circle of 125 m of radius, the centripetal force on the car is 40,000 N (this force equals friction and it can be determined). What is the speed of the car? (Answer: v=100m/s)
Fc = ((m) (v^2)) /r
40,000 = (500(v^2)) / 125
5,000,000 = 500 (v^2)
1,000 = v^2
100 = v

v = 100 m/s
An object has a mass of 100 kg. What is its weight? (Answer: w=980N)
w = (m) (g)
w = 100 (9.8)
w = 980

w = 980 N
Assume a 30,000 kg object and a 50,000 kg object are 0.03 m apart. Find the gravitational force. (Answer: F=11,117N)
F = ((G) (m1) (m2)) / (R^2)
F = ((6.67x10^-11) (30,000) (50,000)) / (0.003^2)
F = ((6.67x10^-11) (1,500,000,000)) / (0.003^2)
F = (0.10005) / (0.003^2)
F = (0.1005) / (9x10^-6)
F = 11,116.7

F = 11,116.7 N
Converts 100.0 mile/hour into m/s. (Answer: 44.7m/s)
v = (100 mile/hour) (1,609 m/mile) (hour/3,600s)
v = 44.7

v = 44.7 m/s
Converts 100.00 m/s into mile/hour. (Answer: 224 mile/hour)
v = (100 meter/second) (mile/1,609m) (3,600s/hour)
v = 224

v = 224 mile/hour
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