Download study guide for midterm - OldTurnpikeGradeEightScience

NAME:________________DATE:___________________PERIOD:____
TO COMPLETE THIS STUDY GUIDE, USE YOUR PREVIOUS STUDY
GUIDES!!
1. Variables
In a scientific experiment, the dependent variable is the
_________________________________________________________
_________________________________________________________.
The independent variable is the
_________________________________________________________
_________________________________________________________.
Design an experiment and define the dependent and independent variable:
2. Calculating Speed:
The equation for speed is
Joe runs 200 meters in 60 seconds. What is his speed? Remember to
include units.
3. Speed Graphs:
To determine the speed of a moving object on a speed graph, locate the spot
where the line intersects 1 second on the x axis. Then draw a line over to
the y axis. The place where your line intersects the y axis is the speed.
CONTINUED ON THE NEXT PAGE
1
What is the speed of runner A? Include units
4. Collecting Data About Moving Objects
t= time
t=
x = position
x=
v=
v=
a=
CONTINUED ON THE NEXT PAGE
2
When you graph this information, x is always on the y axis and t is always on
the x axis.
You calculate the scale or value of each box using the following equations:
Scale of x axis = highest value of x data
# of boxes on the x axis
Scale of the y axis = highest value of y data
# of boxes on the y axis
The graph of an accelerating object is always a curve.
Fill in the blanks:
T (s)
t (s)
0
XXXX
1
1
2
1
3
X (m)
0
15
35
60
x
XXX
20
25
V
XXX
15
20
v
XXX
XXX
a
XXXX
XXXX
5
Graph the above data and connect the dots. Label the axes.
CONTINUED ON THE NEXT PAGE
3
5. The Acceleration Equation
The acceleration equation is:
Tips:
1. always write the equation first
2. If the problem describes deceleration, be sure you calculate a
negative number
3. Your units should always be distance/time squared.
A car decelerates from 60 mph to 20 mph in .2 hours. What is the car’s
deceleration? Include the units.
6. Forces
Force - a push or a pull that one body exerts on another. Friction and
gravity are forces. Forces cause a change in motion when they are
unbalanced.
Units of force– Newtons or N. 1 N = 1kgm/s2
One Newton is the amount of force required to accelerate a 1 kg mass by 1
m/s2.
Balanced Forces – forces that are equal in size but opposite in direction. An
object at rest has balanced forces acting on it. Balanced forces cause no
change in motion.
Unbalanced Force – forces that are unequal in size and opposite in direction.
Unbalanced forces cause a change in motion.
When drawing a force diagram, forces acting from left to right are positive.
Forces acting from right to left are negative.
CONTINUED ON THE NEXT PAGE
4
Net Force – two or more forces acting on an object at the same time added
together. They do not have to act in the same direction. When net forces
add up to 0, the motion of the object stops changing because the forces are
balanced. When net forces are added and the sum is negative, the forces
are unbalanced and the object moves to the left. When net forces are
added and the sum is positive, the forces are unbalanced and the object
moves to the right.
Draw a force diagram for the following situation:
At the school picnic, two teams are playing tug-of-war. Biff is pulling
from the left with a force 1000 N. Boff is pulling from the right with a
force of 800 N. Boff’s team also has the Tewksbury Tiger pulling from
the right with a force of 600 N. Ms. S is pushing from the left with a
force 110 N. What is the net force on the object?
7. Gravitational Acceleration (g) – the acceleration of all objects falling to
earth is the same and is caused by gravity due to the Earth’s massive size.
The value is 9.8 m/s/s. This means that any object increases its velocity by
9.8 m/s each second that it falls. When air resistance is removed, all falling
objects accelerate with a value of 9.8 m/s/s and hit the ground together
regardless of mass.
CONTINUED ON THE NEXT PAGE
5
8. Energy
Four Types of Kinetic Energy (include their definitions and examples)
Three Types of Potential Energy (include their definitions and examples)
Energy of a Car Rolling Down a Slope
What kind of energy does it have at the top?
What kind of energy does it have at the bottom?
What happened to some of the energy as it rolled down the slope?
9. Calculating KE and GPE
Equation for KE -

Only square the velocity, not the mass!
Equation for GPE -

What is g?
Remember:
 Always always always write the equation first!
 Always include units and double check that they are correct. For
example, mass will always be in kg, energy will always be in Joules,
velocity will always be in meters/second, g will always be in
meters/second squared, and height will always be in meters
CONTINUED ON THE NEXT PAGE
6
a. How much kinetic energy does a 5000 kg wrecking ball have
when it hits a wall at a velocity of 9 m/s?
b. How much energy does a .0001 kilogram fly have when it hits
your windshield at a velocity of 1 m/s?
c. You are riding the world’s steepest rollercoaster. The first
drop is 333 meters. Your mass is 200 kg. How much
gravitational potential energy do you have at the top?
Don’t forget to study your labs, homeworks, notes and the textbook.
Some additional things that may help you are the Jeopardy game on my
website under “Documents Marking Period 2” and Mr. Edmond’s Youtube
song about energy.
Eat breakfast, go to bed early, study in small chunks, quiz yourself, and
don’t panic! Good Luck!
7