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Newtons 2nd Law Acceleration
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ForcesGravity and Newtons 2nd Law
Newtons 2nd Law Acceleration
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Mass = how much matter is in an object
More mass = greater inertia (harder to move or stop)
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Newton's Second Law of Motion
the acceleration of an object is in the same direction as the net force on the object and can be calculated with this equation:
acceleration = net force (in Newtons) mass ( in kg)
Or simply...... a = F/mF = ma
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Practice:1. If you push an object that has a mass of 2kg, and the net force acting on the object is 6N, what is the object's acceleration?
2. If a mass of 5kg is moving at an acceleration of 3m/s2 , what is the force?
Luke, use the mass times the acceleration
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More practice
1. If a helicopter has a mass of 4500 kg and the net force on it is 18000N, what is the helicopters acceleration?
2. A boat being pulled by a truck has an acceleration of 2 m/s2. What is the mass of the boat if the net force on the car is 3000N?
3. A block is being pushed with a force of 10N and its mass is 20kg. What force is acting on the block?
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Friction = a force that hinders the sliding motion between two objects
It keeps these cars from sliding down the hill.
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The amount of friction depends on the masses and the type of surfaces pressing together.
An icy surface has less friction than a dry surface.
Why does putting sandbags in your truck help you to not slide on ice.
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Static friction is what prevents two surfaces from sliding past each other.ex. You push a large box but it just wont move.
Sliding friction is the force that opposes two surfaces that are already sliding.ex. once you get the box moving, it is easier to slide.
click link, then view online button
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Air resistance = a friction like force that affects objects that
The feather has more air resistance, so it falls slower than the elephant.
Do a penny and a bowling ball drop at the same rate?
http://www.visionlearning.com/en/library/Animations
See Galileo's Tower Animation
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If you jump out of a plane, you might use a parachute.
When you first jump out a plane, gravity is the force acting upon you (with some air resistance)
Eventually, the force of the air resistance and gravity is equal and you no longer accelerate. this is called terminal velocity.
animation -->click link, then click view online button
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Newtons 2nd Law Acceleration
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Gravity = the attractive force between two objects: depends on mass and distance
If the objects move farther apart, the force between them decreases.
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Neptune was discovered in 1846 because scientists noticed that Uranus was moving differently than expected. Why? Because there was an unseen object behind it adding its own force to Uranus.
These forces explained why the moon travels around the Earth and not the Sun
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The rate of acceleration at which every object falls to Earth is 9.8 m/s 2
F(gravity) = mass (kg) x acceleration of gravity (m/s 2 )
Eureka Acceleration Video
acceleration video part I
acceleration video part II
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Weight = the gravitational force exerted on an object.
Mass = the amount of matter in an object
Weight = mass x 9.8 m/s 2
It is measured in Newtons
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Weight depends on gravity, which can vary depending on the planet. The force of gravity on the moon is 1/6 th of Earth
So, you would actually weigh less on the moon than you weigh on Earth
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The more mass a planet has, the more gravity it has.
Calculate your weight on each of the different planets by filling in the chart!!