Honor Physics Final Exam

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Terms in this set (...)

Scientific Method
1. Question/ Recognize the Problem
2. Hypothesis
3. Predict consequences of hypothesis
4. Conduct experiment and collect data
5. Conclusion
Fact
an objective observation that cannot be contradicted; a close agreement between competent observations who make a series of observations of the same phenomenon
Hypothesis
an educated guess; specific, quantitative/ qualitative, includes time period
Theory
an explanation of why things happen that is tested, but is constantly undergoing change; a synthesis of a large body of information that encompasses well-tested and verified hypotheses; not set and can undergo change
Accurate
Nearness of a measurement to the accepted true value
Precise
how replicable a measurement is; AKA How close to the same number each measurement is
Dimension
a mesurable extent of some kind
Vector
Deals with both magnitude and direction
Scalar
Describing with a single nimber
gives magnitude only
can be both positive and negative
Resultant
a vector that is the sum of two or more other vectors
- the final point in the process
Velocity
speed in a given direction
Speed
The distance an object travels per unit of time
Mass
the amount of matter in an object
Weigh
how heavy something is
Acceleration
an increase in speed
Displacement
distance and direction of an object's change in position from the starting point
Projectile Motion
the curved path that an object follows when thrown, launched, or otherwise projected near the surface of Earth
Force
A push or pull exerted on an object
Net Force
the combination of all forces acting on an object
Static Friction
friction that acts on objects that are not moving
- resists motion
Kinetic Friction
the force that opposes the movement of two surfaces that are in contact and are sliding over each other
Inertia
the tendency of an object to resist any change in its motion
- a law
Mechanical Energy
the total energy
Gravitational Potential Energy
Potential energy that depends on the height of an object
Elastic Potential Energy
energy stored by something that can stretch or compress
Kinetic Energy
energy of motion
Momentum
the product of mass and velocity
- inertia in motion
Impulse
product of force and time interval during which the force acts.
- Impulse does NOT change in a collision; impulse is the change in momentum
Elastic Collision
When objects collide without being permanently deformed or without generating heat
- Energy is NOT lost; there is no damage to either object
Inelastic Collision
When colliding objects become entangled or coupled together, thereby generating heat or disfigurement
- Energy is lost during the collision (usually due to heat or friction); there is a change in shape
What are the SI units for displacement, mass, time, velocity, acceleration, force, energy, momentum, and impulse?
displacement: meter: m
Mass: Kilogram: Kg
Time: Seconds: s
velocity: meters per sec: m/s
acceleration: meters per sec squared: m/s2
Force: Newtons: N
Energy: Joule: J
Momentum: kg * m/s
Impulse: N*s
What is the difference between distance and displacement? Which is a scalar and which is a vector?
Distance- the total distance traveled
Displacement- the shortest distance from point a to pint b?
Know how to convert to SI units (metric conversions).
G*MKHDDCM*ū**N
What are the 5 steps to the scientific method?
1. Question/ Recognize the Problem
2. Hypothesis
3. Predict consequences of hypothesis
4. Conduct experiment and collect data
5. Conclusion
Give an example of when something is accurate, but not precise?
when you hit the target in different places
Is a fact objective of subjective? Is it usually quantitative or qualitative?
Fact- Objective
- quantitative
Can you have constant velocity and constant acceleration at the same time? Why or why not?
No, because acceleration is change in velocity
- only when your velocity or acceleration ir both is zero
What are 3 ways and object can change it's velocity.
- speed up
-slow down
-chance direction
What are 2 ways an object can have positive constant acceleration? What are 2 ways an object can have negative constant acceleration?
1. speeding up
2. slowing down in the negative direction
1. slowing down
2. speeding up in positive acceloration
Why is acceleration due to gravity always negative?
- it is pushing down
What is a force?
- a push or a pull
What is inertia? Is inertia a force?
- it is a law, the tendency of an object to stay in it's constant state, unless another force acts on it
When the mass is increased, what happens to inertia?
- it increases, directly proportional
How can an object moving and still have inertia?
.- when moving it will stay moving
Why does your body want to keep going forward after an accident when the can has already stopped?
- because of inertia
What do forces produce?
- acceleration
If an object is moving with a constant velocity, what is the net force acting on it?
- 0
Give an example of something with no net force acting on it but still moving?
- a ball rolling acros a frozen pond
When you increase the mass of an object but apply the same amount of force, what happens to the acceleration?
- the acceleration goes down
When an object moves in a circle, in which direction does the force point? What is the name of that force?
- out, centripetal force
Why would you not require a seat belt to remain in your seat during a loop-de-loop on a roller coaster?
- centripital force forces you out towered the tract into your seat
What is friction?
- a force that acts to resist motion of object, or material of contact
Which will have a bigger coefficient of friction, rubber on a dry concreate or rubber on wet concreate?
- dry
What is a free body diagram and what is it used for?
- a drawing with all forces, to show all fouces acting on it
What forces are shown on a free body diagram?
- all fouces, tention, norma, applied, friction, cintripial, weight
What type of force is air resistance?
- friction
The force influenced by gravity is called what?
- weight
What is the name of the force that results from a surface pushing back on an object?
- normal
What is an object's net force when it is equilibrium?
- 0
List Newton's three laws of motion in YOUR OWN WORDS and gives examples of each.
1. inertia, an object that moves will keep moving, and object at rest will not move, unless another force acts on it
- a ball rolling across a frozen pond, it dose not slow down
2. F=ma, acceleration and mass are directly proportional to force
3. for every action there is an equal opposite reaction
What is the normal force of an object in free fall.
- 0
What is the difference between static and kinetic friction?
- static, non moving, the object it still
- kinetic, moving
What is the coefficient of friction? What are it's units? Is the coefficient of static and kinetic friction always bigger between two objects? Why?
- mu
- no units
- static
Name 3 action-reaction pairs?
-a car pushing on the earth, the earthing pushing back on it
- two people pushing off each other on ice
- a gun shooting out a bullet
If a truck and a car collide together, which has a bigger force? What has the bigger acceleration?
- same force
- car bigger acceleration
What is the difference between mass and weight? Which one changes with location? Which one remains the same no matter what?
- mass is amount of matter, reamins the stame
- weigh relative to gravity, pushing down, changes with location
What is projectile motion?
the curved path that an object follows when thrown, launched, or otherwise projected near the surface of Earth
Gibe 3 examples of projectiles?
- a man being shot out a a cannon
- a gun shooting out into the are
- throwing a ball in the air
If a bullet is fired horizontally and another is dropped from the same height, which bullet will hit the ground first?
- same time, because same vertical speed
In the vertical direction, is a projectile moving at a constant velocity or acceleration? Why?
- constant acceleration
In the horizontal direction, is a projectile moving at a constant velocity or acceleration? Why?
- constant velocity
What is the unit of energy?
- J Joules
What is the difference between apparent weigh and actual weight? What does a scale tell you?
- apparent is based on normal weigh at the moment in time and place, scale tells you
- actual weigh is just what you weigh no matter what
As an elevator accelerates up to the top floor?, what happens to your actual weight? What about your apparent weigh?
- it gets bigger apparent, same actual
As an elevator moves with a constant velocity down towards the bottom floor, what happens to your actual weight?
What about your apparent weigh?
- actual stays the same
- apparent weigh gets smaller
What is kinetic energy?
energy in motion
If a car is traveling 30 mph needs 100 meters to stop, how much room does it need if it going at 60 mph? How about a 90 mph?
60- 400
90- 1600
What is the difference between elastic and gravitational potential energy?
elastic- the potential to be snap back
gravitational potential energy- has potential to fall
Does a stretched out slinky on a table have gravitational or elastic potential energy?
- both
If a rock in a sling-shot has 700 J of potential energy, what type of potential energy is it? How much kinetic energy will the sling-shot have after it is fired without air resistance? With air resistance?
- elastic
-700 J
- less than 700 J
Describe the energy transformations as a pendulum swings back and forth.
- Ug to K
Is momentum a scalar or a vector quantity?
- vector
What is impulse?
product of force and time interval during which the force acts.
- Impulse does NOT change in a collision; impulse is the change in momentum
Compare the momentum of a large truck moving 30 mph to the momentum of the same truck moving at 90 mph.
- 90 mph, 3 times grater
How are impulse and momentum related?
- impulse is change in momentum
How does bouncing increase the impulse?
- it does not
What do you bend your knees when you land?
- to increase time, and decrease force
When would the momentum of a system not be conserved?
- when energy is lost, due to outside forces acting on it, work is done
If you are in space (frictionless) and you throw an object that is less massive than you, which will move away faster, you or the object? What if the object is more massive than you? What if the object is the same mass as you?
- the object
- you
- both the same
A 5 kg cart moves with a velocity of 4 m/s to the left. What is the momentum of the cart?
- p=-20
Compare elastic and inelastic collisions.
elastic- no damage or hear, bounce
inelastic - stick together, or warping, energy losy
Which type of collision does not have conservation of mechanical energy? What happens to that energy then?
- inelastic
- it is lost to heat, energy
What type of collision takes place with the Newton's Cradle? What type of collision takes place with car crashes?
- elastic
-inelastic
Explain conservation of momentum in your own words.
- momentum stays the same though a system, same in the beginning and end, unless outside forces
If a ball has momentum, it must also have what type of energy?
- kinetic
If you fell through the center of earth what happens to your speed as you approach the Earth's center? What about as you move away?
- less acceleration, less speed
- acceleration decreases, less speed
What is your weight in the middle of the earth?
- 0 N
Will you weigh more or less in an elevator accelerating up?
- more
Will you weigh more or less in an elevator moving at a constant speed up?
- the smae
What does weight really measure?
- amount of gravity