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76 Cards in this Set
- Front
- Back
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What type of forces cause a change in motion and wat type of forces cause NO change in motion? |
Unbalanced and Balanced forces |
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What are 5 different ways forces can change motion? |
speeding up, slowing down, starting, stopping, changing direction |
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Give an example of contact and non-contact forces |
Contact would be pushing someone or hitting someone Non-contact would be gravity and magnetic |
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Types of friction |
Fluid, static, rolling, sliding |
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what causes friction and what does it depend on |
small bumps, dips, surface, force |
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why is friction a necessary force |
Without friction we wouldnt be able to slow down and stop |
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what effect does distance have on gravity |
the greater the distance the less gravitational pull on an object |
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what effect does mass have on gravity |
The greater the mass the greater pull on the object |
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what effct does mass have on inertia |
The greater the mass the greater Inertia |
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Examples of Newton's First Law |
Rain falling, car stopping, running in to a wall |
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Give an example of Newton's Second Law |
a girl pushing a sled and it accelerates, the motion of a satellite as it orbits the earth |
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Give an example of Newton's Third Law |
Walking, Running, Jumping |
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true or false: you push on a book and it moves. The forces acting on it must be balanced forces. |
False the answer is Unbalanced |
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True or false: When you push downward on Earth to make a pole vault, Earth exerts an equal force on the pole. |
True |
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True or false: The acceleration of an object is always in the direction of the net force acting on it. |
True |
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True or false: Cars, Airplanes wings, and bike helmets are built in a streamlined shape to reduce inertia. |
False Air resistance |
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True or false: Acceleration is caused by balanced forces |
False unbalanced |
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True ot false: Friction is a force that speeds up motion between two surfaces that are in contact |
False slows down |
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True or false: An object with a mass of 9.0 kg has an acceleration of 3 m/s^2. The force acting on it is 3N |
True |
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True or false: Sliding friction keeps an object at rest |
False static friction |
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True or false: Is an unbalanced force is acting on a rope, the rope will accelerate in the direction of the unbalanced force. |
True |
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True or false: A car goes around a curve at a constant speed. There is not a net force acting appon it |
false there is |
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True or false: When you ride your bike around a corner at 10 m/s, you are accelerating |
True |
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True or false: A ball is thrown horizontally. Gravity causes the ball to fall to the ground and follows a curved path. |
True |
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Which of the following is not an example of curcular motion and why? A. car turning a corner B. yo-yo on a string going in a circle C. car accelerating onto a highway D. the Moon's path around Earth |
C. A car accelerating onto a highway because this is not an example of something going in a circle |
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What is Newtons second law of motion and what is the equation |
Acceleration is produced when a force acts on a mass. The greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object). The formula is F=ma
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What is the equation for momentum |
p=m x v kg m/s |
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If gravity did not affect the path of a horizontally thrown ball, the ball would what? |
Travel Horizontally |
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Unbalanced forces can make an object accelerate by what? |
changing its speed and changing its direction |
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The upwards force of an object falling through the air is what? |
Air resistance |
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A moving train car collides with another train car that is motionless on the track. The train cars are the same size. How does the final momentum of the two cars compare to the momentum of the first car? |
It is the same |
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The force that opposes motion is what? |
Friction |
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What is the momentum of a 250 kg motercycle traveling at 25 m/s? |
6250 kg & #8729;m/s |
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When two birds are pulling on a worm and the worm moves toward the first bird, you know that the forces are what? |
Unbalanced |
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The force you have to overcome to start an object moving is what? |
static friction |
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What is an example of a non-contact force? |
Gravity |
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Forces that are equal in size but opposite in direction are what? |
balanced forces |
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An unbalanced force acting on an onject causes it to what? |
accelerate |
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The statement "for every action is an equal and opposite reaction" is a statement of what law? |
The third law |
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What is a force o motion that is involved in the Moon orbiting the Earth? |
a force pulling the Moon towards the center, a speed at right angles to the line from the mass of the moon to the center of Earth, and acceleration toward the center of Earth |
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Whenever an object exerts a force on another object, the second object exerts a force of the same magnitude, but in the ___ direction to that of the first object? |
Opposite |
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A skater slowing as she slide across the ice is an example of _. |
friction |
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A 300-N force acts on a 25-kg object. The acceleration of the object is _. |
12 m/s^2 |
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A 3,000-N force gives an object an acceleration of 15 m/s^2. The mass of the object is __. |
200 kg |
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A planet is discovered that is the same size as earth and has the same gravitational acceleration, but has twice the mass. If you weigh 700 N on earth, on the new planet you would weigh? |
1,400 N |
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For every action ther is a what? |
An equal and opposite reaction |
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An arrow can be used to represent a force. The length of the arrow represents what? |
the strength of the force |
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A collision is considered elastic if? |
the objects do not stick together |
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Fred (m= 67 kg) foolishly attempts to jump from a conoe (m= 45 kg) to the dock. If he jumps forward with a speed of 3.3 m/s, how fast will the conoe move backward? |
4.9 m/s |
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An object of large mass has ___ than an object of a small mass. |
More momentum |
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Two toy cars that have the same mass and same speed move toward each other, collide, and stick together. After the collision, the momentum of the cars is ___. |
the same as the originial momentum |
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The unit of force is what? |
The newton |
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Give an example of an unbalanced force |
a person in a elevator going down |
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what keeps a satellite in orbit? |
centripetal force |
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which is a force? Momentum, friction, velocity, or acceleration |
friction |
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A student hits a nail with a hammer. Durring the collision, there is what? |
a force on the nail and the hammer |
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The relationship among force, mass, and acceleration is stated in what? |
Newton's second law of motion |
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force |
a puh or pull on an object |
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Contact force |
a push or pull on an object while touching it |
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Non-contact force |
A push or a pull on an object without touching it |
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Balanced forces |
when the force applied on bothsides is equal |
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Unbalanced forces |
When the force applied on both sides is not equal |
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Gravity |
an attractive non-contact force that exists between two object with mass |
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Mass |
how big an object is |
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Weight |
How much gravity is applied on an object |
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Friction |
A contact force that resistes the motion when two objets are touching |
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Net force |
the sum of both forces |
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Inertia |
The force that makes you want to keep moving when the outside object has stopped |
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Circular motion |
is a movement of an object along the circumference of a circle or rotation along a circular path |
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Centripetal force |
centripetal is a force that pull the objects in. |
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Force pair |
forces two objects apply on eachother |
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Momentum |
a measure of how hard it is to stop a moving object |
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Law of conservation of momentum |
The total momentum of a group of objects stay athe same unless outside forces act on the objects |
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Newtons first law |
An object in motion stays in motion and an object at rest stays at rest unless acts on by an outside force |
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Newton's second law |
Acceleration is produced when a force acts on a mass. The greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object).
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Newtons thirs law |
for every action is an equal and opposite reaction |
