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Interaction
A mutual action between objects where each object exerts an equal and opposite force on the other
Newton's third law of motion
states that whenever one object exerts force on a second object, the second object exerts an equal and opposite force on the first object
action force
one force in an interaction
reaction force
the other force in an interaction
Mathematical Principles of Natural Philosophy
The title of Newton's book was _______.
Name two things that were discussed in Newton's book
3 laws of motion and the laws of gravity
Pairs
Forces always come in _______
Interactions
A force is not an isolated happening but is part of an _______ between two objects
Action-reaction pairs
Two forces that have equal strengths but opposite directions are called _______.
Strength; opposite; at the same time
Action-reaction forces are equal in _______, _______ in direction and occur _______.
State Newton's third law
For every action, there is an equal and opposite reaction
Feet pushing on earth and earth pushing back on feet
What are the action and reaction forces that are present when you walk?
The road pushes on the car
When the tires of a car push on the road (action), what is the reaction force?
The boulder pulls up on the earth
When a boulder falls toward the Earth, the action is the gravitational pull of the Earth on the boulder--what is the reaction force?
When you lift a bucket of water, name two pairs of action-reaction forces?
Gravity pulls down on bucket, bucket pulls up on earth; bucket pulls on hand, and hand pulls on bucket
The gasses push up on the rocket
When a rocket flies, the action force is the rocket pushing on the gases coming from the tail of the rocket. What is the reaction force?
Forces cancel out when...
They act equally on the same object
They act on different objects
Action-reaction forces don't cancel out because.....
The force exerted by the horse on the carrt
When a horse pulls on a cart, what is the action force?
The force exerted by the cart on a horse
What is the reaction force to a horse pulling a cart?
The horse exerts a force on the ground
If a horse pulls the cart with 10 N of force, and the cart pulls on the horse with 10 N, how does the horse pull the cart?
gravity
(physics) the force of attraction between all masses in the universe
Our mass is so small compared to the earth
Why d on't you feel the Earth move when you step off a curb?
The force that the bullet exerts on the riffle
When firing a riffle, the force the riffle exerts on the bullet is equal but opposite to...
What does a gun "kick" when it's fired?
Because the bullet exerts a force on the gun
Force; mass
Newton's second law reminds us that in acceleration, we must consider both _______ and _______.
Because it has less mass
Why would a bullet fired from a gun undergo more acceleration than the gun?
a=F/m
Newton's second law (equation)
They're equal
When a gun is fired ,which force is larger, the one on the gun, or the one on the bullet?
Big
A force with a small mass has a _______ acceleration
Small
A force with a big mass has a _______ acceleration
Inversely
Acceleration is _______ proportional to mass
Robert Goddard
Who is the father of Modern Rocketry?
He much a machine gun on a wire in a vacuum and started firing.
What was Robert Goddard's famous experiment that showed how a rocket would work in space?
The gun moved up the wire
What was the result in Goddard's experiment?
Why did the gun do what it did in Goddard's experiment?
Because the bullets pushed off the gun and the gun pushed off the bullets
Because there's no air in space
Why did people think that it was impossible for rockets to go to the moon?
A computer
What instrument is used to calculate a rocket's path?
The air pushing on the wings
When a bird flys, the action reaction force is their wings pushing the air downward, what is the reaction force?
Pushes against the ground
In a tug of war, the team that wins is the team who...
It accelerates
How do you know that a force is action on a falling object?
Halfway
If you dropped a piece of clay that was as massive as the Earth, how far would it fall toward the earth?
Why can't you hit a piece of paper with 200 N?
You can't get a 200 N interaction from a piece of paper
200 N
A100-N force is used to accelerate a large push cart across the floor. What force is required to accelerate the push cart twice as fast.
Minute
A bug splatters on your windshield. Compared to the force of the car on the bug, the force of the bug on the car is _______
Bike; Bike
If a bicycle and a large truck have a collision, upon which vehicle is the impact the greatest? Which vehicle undergoes the greatest change in motion?
You're pushing against the log.
If you walk on a log that is floating in the water, the log moves backward. Why?