Download Newtons 3 Laws of Motion - Saint Mary Catholic School

8th Grade Mid Term 2014 Review
Vocabulary for Mid Term:
Celsius, conduction, conductor, convection, energy, heat, infrared, insulation
radiation,temperature,thermal energy,thermometer,current,radiant energy,
matter, mass, kilogram, balance, weight, gravity, pressure, temperature, volume,
specific gravity, substance, chemical change, gas, liquid, matter, molecule,
plasma, physical change, solid
acceleration
friction
inertia motion
matter
kinetic energy
balance
gravity
energy
mass
weight,
potential energy
Newtons 3 Laws of Motion
Reaction Type:
decomposition
c. single replacement
Formulas
Ko= Co + 273
Fo = 9/5 Co +32 Co = 5/9(Fo-32)
d. double replacement
e. combustion reaction
Calculate for Density:
1. State the formula for density in words and mathematical
symbols.
2. A rock has a mass of 210 grams and occupies a volume
of 70 cm3. What is its density?
DENSITY:
The density can be expressed as
ρ = m / V = 1 / vg
(1)
where ρ = density (kg/m3) m = mass (kg)
V = volume (m3)
3. An unknown liquid occupies a volume of 5 ml and has a
vg = specific volume (m3/kg)
mass of 40 grams. Find its density.
4. A rock occupies a volume of 20 cm3 and has a mass of
54 grams. Find the density of this rock.
5. A rock has a density of 4 g/ml and a mass of 16
grams. What is the volume this rock occupies?
Specific Weight is defined as weight per unit volume. Weight is a force. Specific Weight can
be expressed as
γ=ρg
where γ = specific weight (N/m3) ρ = density (kg/m3)
g = acceleration of gravity (m/s2)
Using the Equations for Potential Energy and Kinetic Energy please solve the following questions:
Determine the kinetic energy of a 1000-kg roller coaster car that is moving with a speed of 20.0 m/s.
Missy Diwater, the former platform diver for the Ringling Brother's Circus had a kinetic energy of 15,000 J just prior to hitting
the bucket of water. If Missy's mass is 50 kg, then what is her speed?
The potential energy of a 40-kg cannon ball is 14000 J. How high was the cannon ball to have this much potential energy?
A 75-kg refrigerator is located on the 70th floor of a skyscraper (300 meters above the ground) What is the potential energy
of the refrigerator?
Fill in the Blank:
Kinetic Energy is: __________________
Potential Energy is: ____________________
List two examples of Kinetic Energy from Universal Orlando: _____________
List two examples of Potential Energy from Universal Orlando: ______________
List an example from Universal Orlando in which Potential Energy turns into Kinetic Energy:
_________________________________________________
What is the difference between potential energy and kinetic energy? ________________
When calculating a formula you are given g for gravity. What does g equal? _____________
What is gravity and how does the force of gravity affect objects on Earth and in our Solar System?
What is friction and how does friction affect the motion of an object?
Working on balancing Equations some more…with Hints
How to balance equations (the very brief version):
Write down a chart of all the elements before and after the arrow
l it is
Things to try if the equation doesn't balance:
rut and can't see what you're doing wrong. Start over and get a fresh start.
rk. If you're doing this in your head, you're probably making mistakes at some point. Yes,
I know that it messes up your paper, and I know that it looks sloppy, but it works.
licated looking formula.
This often forces you to get a fresh perspective on the problem. If that doesn't work, try putting a “3”
and so on.
anything. This isn't a big deal, so take some chances!
1)
2)
4.
5.
_____ N2 + _____ H2 → _____ NH3
_____ NaCl + _____ H2SO4 → _____ NaHSO4 + _____ HCl
_____ KMnO4 → _____ K2MnO4 + _____ MnO2 + _____ O2
_____ AgF + _____ CaCl2 → _____ AgCl + _____ CaF2
ON Discovery Education you also have a multiple choice assignment called Mid Term Multiple
Choice. Please practice these questions as they will appear on your mid term
Using the Equation for Speed and Acceleration work through the below problems:
A car starts from a stoplight and is traveling with a velocity of 10 m/sec east in 20 seconds. What is
the acceleration of the car?
1. First we identify the information that we are given in the problem:
vf - 10 m/sec
vo - 0 m/sec
time - 20 seconds
2. Then we insert the given information into the acceleration formula:
a = (vf - vo)/t
a = (10 m/sec - 0 m/sec)/20 sec
3. Solving the problem gives an acceleration value of 0.5 m/sec2.
Now try on your own:
1. What is the speed of a rocket that travels 9000 meters in 12.12 seconds? 742.57 m/s
2. What is the speed of a jet plane that travels 528 meters in 4 seconds? 132 m/s
3. How long will your trip take (in hours) if you travel 350 km at an average speed of 80 km/hr? 4.38
h
4. How far (in meters) will you travel in 3 minutes running at a rate of 6 m/s? 1,080 m
5. A trip to Cape Canaveral, Florida takes 10 hours. The distance is 816 km. Calculate
the average speed. 81.6 km/h
6. How many seconds will it take for a satellite to travel 450 km at a rate of 120 m/s? 3,750 s
7. What is the speed of a walking person in m/s if the person travels 1000 m in 20 minutes? 0.80 m/s
8. A ball rolls down a ramp for 15 seconds. If the initial velocity of the ball was 0.8 m/sec and the
final velocity was 7 m/sec, what was the acceleration of the ball ? 0.413 m/s²
9. A meteoroid changed velocity from 1.0 km/s to 1.8 km/s in 0.03 seconds. What is the acceleration
of the meteoroid? 26.7 km/ s²
10. A car going 50mph accelerates to pass a truck. Five seconds later the car is going 80mph.
Calculate the acceleration of the car. 6 mph/s
11. The space shuttle releases a space telescope into orbit around the earth. The telescope goes from
being stationary to traveling at a speed of 1700 m/s in 25 seconds. What is the acceleration of
the satellite? 68 m/s²
12. A ball is rolled at a velocity of 12 m/sec. After 36 seconds, it comes to a stop. What is the
acceleration of the ball? -0.33 m/s²
13. How much force is needed to accelerate a truck with a mass of 2,000 kg, at a rate of 3 m/s²? 6,000 N
14. A dragster in a race accelerated from stop to 60 m/s by the time it reached the finish line. The
dragster moved in a straight line and traveled from the starting line to the finish line in 8.0
sec. What was the acceleration of the dragster? 7.5 m/s²
15. A 300 N force acts on a 25 kg object. The acceleration of the object is 12 m/s²
Know ALSO the following vocabulary terms:
Constant speed – Speed that does not change
Velocity – Speed in a given direction
Frame of reference – A background used to judge motion or speed
Instantaneous Speed – Speed at a given moment in time
Speed – amount of distance traveled in a certain amount of time
Average Speed – total distance divided by total time
Time-Distance Graph – graph that shows speed of an object
Acceleration – change in velocity over time
Motion – an object changing position or distance in time
Rate of Change – amount of time it takes to change position or motion
Inertia - tendency of a still object to stay still or miving object to keep moving unless acted on by an
unbalanced force
Force – push or pull
Centripetal Force – force keeping objects moving in a circle
Gravity – pull of objects in the universe – pull determined by mass and distance
Newton’s Three Laws of Motion – 1st: Law of Inertia (see Inertia definition); 2nd: Force=mass x
acceleration;
3rd: For every action, there is an opposite and equal reaction