# Physics 010

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1. Define Physics
The study of how things in the world work pertaining to matter and energy.
2. Define Mechanics
The explanation of how an object is moved or displaced.

• Acceleration
• forces
• energy
• work
• mass
3. Define a scalar
A quantity that can be described by a singular number giving its size or magnitude and has no direction.

Ex.  The number of days in a week.
4. Define a vector
A quantity that deals with both a magnitude and a direction and is described as a vector quantity.
5. What is an important characteristic of a vector and why is it important?
Direction of an arrow is an important characteristic of a vector because the arrows represent the direction of the vector and the length of that arrow represents the proportional magnitude of the displacement (X) of that vector.
6. Define displacement and what is its SI unit?
A vector qty that has direction that points form an objects initial position (X, V, T, A) towards its final position (X0, V0, T0, A0) and has a magnitude that equals the shortest distance between the two positions.  (the objects overall change from point A to point B).

Its SI unit is, (m) meters
7. Are two vectors with the same magnitude necessarily equal?
No, The two vectors with the same quantity and magnitude would have to be going in the same direction to be equal.
8. What are examples of scalars and vectors?
• Distance
• Displacement
• Speed
• velocity
• acceleration
9. Define distance
A scalar qty that refers to how much ground an object has covered during its motion.  Scalars do not have direction.
10. Define speed and give its average speed equation.
Average speed is the total distance traveled divided by the total time required to travel that distance. Speed is scalar qty that refers to "how fast an object is moving".

Av=total distance/total time
11. Average velocity
average velocity is a vector qty that refers to the rate at which the displacement changes.

SI units; (m/s)

If an object is changing its velocity -whether by a constant amount or a varying amount - then it is an accelerating object.
12. Constant velocity
an object with a constant velocity is not accelerating
13. Define instantaneous speed.
instant speed-- at any given instant in time (now).
14. Define acceleration and what is its equation?
Rate at which the velocity changes.  acceleration is a vector qty that has a direction associated with it. average acceleration represents the slope of the straight line from initial to final points on a velocity.

SI unit; m/s2
15. free fall G=m/g
An acceleration of an object near the earths surface is constant and known as acceleration due to gravity or G's.

An object that is free falling is 9.8 m/s2, pointing down.  An object that is climbing is -9.8m/s2 is climbing.
16. For an object to accelerate
It must

• speed up.
• slow down
• or change directions
17. define enertia
the tendency of an object to remain at rest or in a constant motion in a straight line unless acted upon by an unbalanced force

The tendency of an object to resist acceleration.
18. Newtons first law
an object at rest stays at rest or an object in motion stays in motion with a constant velocity.

No net force no accelaration
19. define a net force
a vector sum of all the forces
20. Newtons second law (laws of force,mass and acceleration)
The accleration of an object depends upon its mass and the magnitude of the force applied to it.

F=M*A

SI units=Newtons (1kg=m/s2)
21. Newtons 3rd law (law of action and reaction)
For every action is an equal and opposite reaction

F12=-f21

• forces always comes in pairs
• the action and reaction forces act on different mass.
22. work
• a force that acts upon an object to cause a displacement at a constant force.
• work will be used from a perspective of work and energy.

Work=force*displacement*cos
23. work with theta cos
a force acts in the same direction as another object, the angle would be 0 degrees.

A force acts in opposite directions of each other would be 180 degrees.

A force that acts upwards on another object the angle would be 90 degrees

A vertical force never does work on a horizontal displacement of 90 degrees
24. work values
• No displacement---no work
• no force--- no work
• if =90---- no work
• if <90 positive work
• if > 90 negative work
25. What does work require?
Work requires that a force acts over a distance.  If an object does not move at all, there is nor displacement, and therefore no work.
26. Force exerted in the opposite direction
A force exerted in the opposite direction to the displacement of an object is negative work.
27. kinetic energy
energy that an object has doe to it's motion....

No motion, no kinetic energy

KE=1/2mv2  joules
28. work and kinetic energy
the network done on an object is equal to the change in the kinetic energy of the object.

wnet=1/2mv2-1/2mv2
29. work-energy theorem
when a net force does work on an object, the kinetic energy of the object changes from its initial value of KE to a final value KE.  the difference between the two values equal to the work.

W=KEf-KEo=1/2mv2-1/2mvo2
30. Potential energy
• an object that possesses some energy supplies the force to do the work
• ------stored energy
31. potential energy
• an object that possesses some energy supplies the force to do the work
• ------stored energy
32. Gravitational potential energy
Gravitational potential energy PE=mgh

The energy that is stored in an object as the result of its vertical position or height. depends on mass and height of the object.
33. Elastic energy
Elastic potential energy PE spring=1/2kx

energy stored in elastic materials as the result of their stretching or compressing depends on the force of the stretch (x) and the spring constant (equilibrium of K)

The more stretch, the more energy stored
34. power
power is the rate at which work is done, It is the work/time ratio.

SI units=watts

Power= force * velocity

SI units= watts
 Author: msmit458 ID: 204691 Card Set: Physics 010 Updated: 2013-05-10 21:26:45 Tags: Physics 010 Folders: Description: Physics Show Answers: