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Gravity
BMS 8th Grade This set includes notes on... ...Motion ...Forces and Newton's Laws Test Date: November 11, 2013
Terms in this set (69)
An object is in motion if it changes ___ relative to a(n) ___.
position; reference point
To calculate the speed of an object, divide the ___ the object travels by the amount of ___ it took to travel the distance.
distance; time
If the speed of an object does not change, the object is traveling at a ___ speed. (The speed of most objects is not ___.)
constant; constant
___ speed is the total distance an object travels divided by the total amount of time it took to travel the distance.
Average
When you know both the ___ AND ___ of an object's motion, you know the ___ of the object.
speed; direction; velocity
Ex.
50 km/hr N
Speed= ___/___
Speed=distance/time
Distance= ___*___
Distance= speed*time
Time= ___/___
Time= distance/speed
You can show the ___ of an object on a line graph in which you plot ___.
motion; distance versus time
In science, acceleration refers to ___ speed, ___ speed, or changing ___.
increasing; decreasing; direction
Any object that is moving in a circle (Merry-Go-Round, moon) is ___ because it is constantly changing direction (even if its speed stays constant).
accelerating
To determine the acceleration of an object moving in a straight line, divide the change in speed (___) by the amount of time it took for the speed to change.
final speed-initial speed
The ___ of a velocity-vs-time graph is the acceleration of the object.
slope (rise over run)
A downward slanted line on a velocity vs time graph indicates ___ speed. The slope of the line is the ___.
decreasing; deceleration
An upward slanted line on a velocity vs time graph indicates ___ speed. The slope of the line is the ___.
increasing; acceleration
A horizontal line on a velocity vs time graph indicates ___ speed (zero slope = ___).
constant; zero acceleration
Acceleration= (___-___) / ___
(final speed-initial speed) / total time
A force is a ___.
push or pull
Every forces has two components:
•How ___ the force is (in Newtons)
•The ___ in which the force acts
strong; direction
The strength of a force is measured in ___.
Newtons (N)
The combination of all forces acting on an object is called the ___.
net force
If the net force on an object is zero, the forces are said to be ___. Balanced forces ___ the object's motion.
balanced; do not change
If there is a non-zero net force acting on an object, the forces are said to be ___. These forces acting on an object will cause the object to ___ (speed up, slow down, or change direction).
unbalanced; accelerate
___ is the force that two surfaces exert on each other when they rub against each other. It always acts in the direction ___ an object's motion. The two factors that affect friction are the ___ involved and ___.
Friction; opposite; types of surfaces; how hard they are pushed together
___ is a force that pulls all objects toward each other. Two factors affect the gravitational attraction between two objects: the ___ of the objects and the ___.
Gravity; mass; distance between them
Newton's First Law: ___
An object in motion will remain in motion and an object at rest will remain at rest unless acted on by an unbalanced force.
Newton's First Law tells us what an object will do when it has ___ forces acting on it.
balanced; Law of Intertia
Newton's First Law is also called the ___.
Law of Inertia
Inertia is the tendency of an object to ___ in its motion.
resist a change
Inertia is dependent on ___. The greater an object's mass, the more the object ___ a change in its motion.
mass; resists
Newton's Second Law: ___
The acceleration of an object depends on the net force acting on it and its mass.
Newton's Second Law tells us what an object will do when it has ___ forces acting on it.
unbalanced
A net force acting on an object will cause the object to ___ (speed up, slow down, or change direction).
accelerate
The greater the net force acting on an object, ___ of the object will be.
the larger the acceration
The larger the object's mass, the ___ required to accelerate the object.
greater the force
Newton's Second Law is also written as a math equation: ___.
Force=Mass*Acceleration
(F=ma)
Newton's Third Law: ___
For every action there is an equal and opposite reaction.
If one object exerts a force on a second object, the second object always exerts a force of ___ strength in the ___ direction on the first object.
equal; opposite
Action - reaction forces are not the same as ___ forces. Action - reaction forces do not cancel each other out because they are ___. Balanced forces are acting on the same object so they will ___.
balanced; acting on two different objects; cancel each other out
kg/m/s^2= ___
(kilograms per meter per second-squared)
Newtons (N)
___ put things in motion.
Forces
"Harder to move" is a property of matter called ___.
inertia
In zero gravity, do the Laws of Motion still apply?
Yes, objects with zero gravity like space stay in motion unless slowed down by something else.
The unit of measurement for m, cm, km is ___.
distance
The unit of measurement for s, min, h is ___.
time
The unit of measurement for m/s, mph is ___.
speed
The unit of measurement for m/s^2 is ___.
acceleration
The unit of measurement for N is ___.
force
The main difference between speed and velocity is ___.
Speed is how fast something is going (20mph). Velocity is speed
and
direction (20mph W).
Acceleration is a ___ line on a graph.
horizontal
Deceleration is a ___ line on a graph.
downward slanted
Which law is it?
You run into your friend while in-line skating, and both of you fall in opposite directions.
Third Law: For every action there is an equal and opposite reaction.
Which law is it?
A book left on the table overnight is there when you return in the morning.
First Law: An object in motion will remain in motion and an object at rest will remain at rest unless acted on by an unbalanced force.
Which law is it?
A baseball hit with a bat flies farther than a bowling ball hit with a bat.
Second Law: The acceleration of an object depends on the net force acting on it and its mass.
Which law is it?
A space shuttle propels gas particles out the back of the shuttle and is able to travel forward in space.
Third Law: For every action there is an equal and opposite reaction.
Which law is it?
A balloon flies forward when air quickly escapes from it.
Third Law: For every action there is an equal and opposite reaction.
Which law is it?
A soccer ball continues to roll until it hits something.
First Law: An object in motion will remain in motion and an object at rest will remain at rest unless acted on by an unbalanced force.
Which law is it?
The bike you are riding hits a hole and stops quickly, but you fly forward over the handlebars.
First Law: An object in motion will remain in motion and an object at rest will remain at rest unless acted on by an unbalanced force.
Which law is it?
A golfer hits a ping-pong ball and a golf ball. The ping-pong ball flies 10 feet and golf ball flies 50 meters.
Second Law: The acceleration of an object depends on the net force acting on it and its mass.
Which law is it?
The clothes you left on the floor are still there when you come home from school.
First Law: An object in motion will remain in motion and an object at rest will remain at rest unless acted on by an unbalanced force.
Which law is it?
A baseball hit with a wooden bat flies farther than a baseball hit with a plastic bat.
Second Law: The acceleration of an object depends on the net force acting on it and its mass.
Predict the motion according to Newton's Laws of Motion. (Second Law)
You hit a ping-pong ball and a tennis ball with a tennis racket with the same amount of force. Which one will travel farther?
Ping-pong ball
Predict the motion according to Newton's Laws of Motion. (First Law)
If you leave a cookie on a plate and there is no one else in the house, where will the cookie be in an hour?
It will remain in the same spot on the plate
Predict the motion according to Newton's Laws of Motion. (Third Law)
If you let the air out of a balloon, what will happen to the balloon?
The balloon will deflate and fly the opposite direction of the air.
Predict the motion according to Newton's Laws of Motion. (First Law)
The horse you're riding stops suddenly. What happens to you?
You jerk forward.
Predict the motion according to Newton's Laws of Motion. (Second Law)
A football player kicks a football and a bowling ball with the same amount of force. What will happen?
The football will go farther than the bowling ball.
Predict the motion according to Newton's Laws of Motion. (Third Law)
Two dodge balls are thrown at full speed and hit each other. What will happen to the balls?
The two dodge balls will repel and bounce back.
Predict the motion according to Newton's Laws of Motion. (First Law)
An astronaut is floating in space where there is no gravitational pull. What will happen to the astronaut's motion?
The astronaut will float in the same place.
A bike rider on a trail travels between the 200 meter and 300 meter trail markers in 20 seconds. What was the average speed of the bike rider during this interval?
Average Speed= Distance/Time
S=(200-300)/20
S=100/20
S=5m/s
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