Forces All you need to know about
Newtons seconds laws
Newton's 2nd law says that it takes more force to move a larger/more massive object. It also says that if you have two equally massive objects and want one to speed up, you will have to apply more force to it. Lastly, if you want to objects to speed up at the same rate, but one object is much larger, you will have to push it harder.
Newton's Third Law
Newton's 3rd Law States that for every action there is an equal and opposite reaction back on the source. Really it means that forces always involve TWO different things/objects interacting, you can't just have ONE by itself.
The unit used for force is
Newtons
Which of these is an example of force?
Pulling a casserole out of the oven
To combine forces in opposite directions ____________ and take the direction of the bigger number
SUBTRACT
All forces have
Strength and direction
Why don't skateboarders keep flying through the air when they launch off a ramp?
The force of gravity works against the skateboarders' inertia.
What can you infer about an object moving at a constant velocity?
The forces acting on it are in balance
If the net force on an object is zero, what can you conclude?
The object is not accelerating
When the forces are balanced, what happens to an object?
The object stays stationary (does not move)
force cause changes in .... so
The speed or direction of an object, we can say that forces cause changes in velocity, so.... Forces cause acceleration!
Newton's Law of Universal Gravitation
The strength of the attraction between two objects depends on the size of the objects and how close they are to each other. The closer two objects are, the greater the strength of the attraction between them. Furthermore the larger an object is, the greater its gravitational pull; in fact we only notice the effect of the gravitational force of massive objects like planets. In other words: When Mass increases gravity INCREASES When Distance increases gravity DECREASES
What is true of non-contact forces?
They become weaker with distance
What is true about all forces?
They involve more than one object
Unbalanced forces cause Acceleration
True
In order for motion to occur the forces must be
Unbalanced
When a net force greater than 0 acts on an object the forces are _________
Unbalanced
Acceleration occurs when an object is subjected to a(n):
Unbalanced force
Which of the following statements is always true?
Unbalanced forces lead to a change in speed or direction
Net Force
We calculate forces using net force. The overall force on an object after all the forces acting on it are added or subtracted .
MASS and NOT WEIGHT?
Well...did you notice in the video demonstration from the astronaut that all of the objects were floating? This means that ALL of the objects had a weight of ZERO. And Newton's 2nd law still worked! The objects are all still made of the same amount of atoms no matter where they are in the universe, so they still have the same mass. So Newton's 2nd law holds true no matter the gravity or weight that it causes, it is all about the mass of the object.
When more than one force acts on an object, what is it called
When more than one force acts on an object, the forces combine to form a net force. The combination of all the forces acting on an object is the net force.
Most magic tricks are really just based on an excellent understanding of math and My. One of the simplest examples is the tablecloth trick and it relies on an understanding of inertia and friction
When the cloth is moved friction also acts on the object. However if the inertia is greater than the friction the tablecloth is whipped free.
Newton's 2nd law says that it takes more force to move a larger/more massive object. It also says that if you have two equally massive objects and want one to speed up, you will have to apply more force to it. Lastly, if you want to objects to speed up at the same rate, but one object is much larger, you will have to push it harder. This is all logical based on your everyday life.
Why does Newton's 2nd Law talk about
Would a house needs a strong force to move it?
Yes
Can more than one force act on an object at a time?
Yes, More than one force can act on an object at a time.
Can the forces push or pull in any direction?
Yes, The forces can push or pull in any direction.
Which is an example of a balanced force?
a book on a table
When an object changes its velocity then it has an
acceleration
How do you calculate the net force acting on an object? *
add forces that are going in the same direction, and subtract forces that are going in opposite directions
Could you push or pull a door?
both
Could you push or pull a shopping cart?
both
Which thing would need a strong force to pick it up? (penny/shirt /soccer ball/cow)
cow
I applied the SAME amount of force to objects with different masses. From the data collected, I saw that as the objects INCREASED in mass (got heavier), the acceleration
decreased
Balanced Forces
equal forces acting on one object in opposite directions (No change in motion) No Acceleration
Which object would NOT need a strong force to move it? (feather/desk/pizza/elephant)
feather
A ______ is a push or pull
force
But what can change an object's motion? Usually motion Is changed with a _______ , which is a push or a pull on an object.
force
SI is the unit of ________
force
Weight
is actually a force caused by gravity. Weight is a measure of the pull of gravity on an object's mass and is measured in Newton (after Isaac Newton!). An object's weight will be different in different places.
Mass
is measured in grams and kilograms and is always the same for an object, no matter where the object is. Mass is a measure of the amount of matter (stuff) that an object contains. When most people talk about their 'weight', what they are really talking about is their 'mass'.
Adding forces is like adding numbers -
it doesn't matter what order you do it in. The mathematical term for this is commutative.
What is the unit of force?
newtons
Do you use a push or a pull when you get a tissue?
pull
Would you push or pull a weed out of the ground?
pull
Would you push or pull an elevator button?
push
Would you push or pull the button on a computer?
push
When one force is pulling down, and the other force is pushing to the right, the direction of the net force is _
south east
Which type of force could make a ball go really far?
strong force
What is net force?
the sum of all of the forces acting on an object
What is an example of friction? slipping on a patch of ice dropping a book on the floor diving into a swimming pool wind blowing against you as you walk
wind blowing against you as you walk
What happens to the object when the forces act, depends on what two things?
→ How strong the forces are → The direction of the forces
Forces can effect motion in what several ways?
→ They can make objects start moving → They can make objects move faster → They can make objects move slower → They can make objects stop moving → They can make objects change direction → They can make objects change shape
Newtons' First Law of Motion says that an object in motion will stay in motion unless acted upon by an outside force. This means that there must be forces acting on a soccer ball to make it stop. Which TWO forces cause a soccer ball to eventually stop moving?
1.Gravity 2. Friction
A big trailer pulls a box 400 N to the left and a little trailer pulls it 200 N to the right. What is the net force? . Is the force balanced or unbalanced?
200 N, Unbalanced
what is a net force?
A net force gives the direction a particle is moving, when more than one force is acting upon it. To find a net force, you must add all the forces together, as it states at
Which of the following is experiencing a net force of zero? A race car driving around a circular track A pencil sitting on a desk A rocket launching into space A person jumping on a trampoline
A pencil sitting on a desk
To combine forces in the same direction-
ADD
What do you do when the forces are acting in the same direction?
Add
How should you calculate the net force of two forces in the same direction?
Add the forces together
When you combine forces going in the same direction you
Add them
Newton's First Law in easy terms:
An object that is moving will keep moving until something stops it. An object that isn't moving will stay the same until something makes it move. How easy or difficult it is to start or stop motion depends on the object's inertia. Inertia is just a word we use for how DIFFICULT it is to move or stop the object.
Which of the following statements is FALSE about an unbalanced force?
An unbalanced force causes an object to change its position, speed or direction.
Net Force can be described as A. The weight of an object. B. When an object is at rest. C. One force acting on an object. D. The overall force acting on an object.
D. The overall force acting on an object.
Which two components must a vector quantity have?
Direction and magnitude
If you drop an egg off of the Empire State Building, which of the following things will happen first?
Drag will increase
First Law of Motion: (Inertia, friction, and gravity)
First Law: Newton's first law of motion states that an object at rest will remain at rest and an object in motion will continue moving in a straight line, at a constant speed, in the same direction, unless an unbalanced net force acts on it. The tendency for an object to resist a change in motion is called inertia. The Force of Friction -The force that occurs when two objects are sliding past one another has a special name. This force is call the force of friction. -Friction is caused by the tiny bumps and irregularities of the surface of one object interacting with the tiny bumps and irregularities of the surface of another object. -The force of friction always acts in the opposite direction of the motion. Gravity: has traditionally been defined as a force of attraction between things that have mass. It prevents you and everything else on Earth from being flung out into space as the planet spins on its axis. It also pulls objects that are above the surface—from meteors to skydivers—down to the ground.
What would you need to move a soccer ball?
Force
Forces are described by _________ and ___________
Forces are described by strength and direction
If the Net force is 0, what can you say about the object?
It is not in motion
Your older brother tells you his paper airplane has inertia. What does this mean?
It will stay in flight unless something stops it, or it will stay still unless something moves it.
If a package has a force of 12 N to the right and 12 N to the left exerted on it, in which direction will it go?
It won't move
5N to the right 10 N to the left. What direction will the object go?
Left
All forces have _______________
Magnitude and direction.
Find the Net Force: 3N --> (100kg) <-- 6N
Net Force: 3N 6-3 = 3
How do you calculate Net Force?
Net force is determined by adding up all of the individual forces on an object. For example, to determine the net force on an airplane, you would add up the lift, weight, thrust, and drag. If forces are in opposite directions, like lift and weight, then you subtract them.
What does the measurement unit N stand for?
Newton
What is the name of the unit you use to measure force?
Newton
What is the unit of measure we use when referring to force?
Newton is the unit of measure for force.
Unbalanced Forces
(Their is a change in motion) And acceleration occurs
When you have an unbalanced force, an object will
(speed up or slow down), or it may change its direction.
-
-
if no forces are applied to the particle and no change in velocity occurs that's called Newton's first law in order to accelerate our particle that is to change its velocity a net force must be applied as with velocity and acceleration forces are also vectors the force due to gravity
-
if there are more forces at work we would add those forces all up to determine the net force and that would determine the direction the particle would accelerate
-
in order to accelerate our particle, that is to change its velocity , a net force must be applied, as with velocity and acceleration, forces are also vectors the force due to gravity
-
How to calculate Net force (add)
--> + --> <-- + <--
How to calculate Net force (subtract)
--> - <-- <-- - -->
When there is a BALANCED force, the net force acting on the object is _____________.
0 N