# Physics/Math Flashcards

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created 6 weeks ago by cwmiller18
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updated 5 weeks ago by cwmiller18
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1

Distance = velocity x time

Finding velocity here gives you the average velocity during the time interval (could be above or below)

2

Net force

Encompases all the forces acting on the object

3

Fk = uk (FN)

Frictional force equation

4

On a horizontal surface what is FN

FN would be FN cos(theta)

5

Kinetic Energy equation

KE = 1/2mv^2

6

Heat energy equation

Q = mcAT

c is specifc heat of the bullet

A is supposed to be delta

7

Total mechanical energy

Involves a combination of kinetic and potential energies - always the same unless some dissipative forces are acting upon it

8

Potential energy of spring systems

PE = 1/2kx^2

9

P = W/t

Power equals watts over time

10

First law of thermodynamics says...

delta U = Q - W

delta U is the chage in internal energy, Q is the heat energy transferred to the body and W is the work done by the system

11

X component vector

X = Vcos(theta)

12

Y component vector

Y = Vsin(theta)

Use this and x component to find the value of the vector using pathagorean theorem

13

Finding the resultant vector

Finding the theta value

pathagorean thereom - for vector addition

use inverse tan of (Y/X)

14

Vector subtraction

would be A - B = A + -(B)

where -B represents a vector with the same magnitude as B but pointing in the opposite direction

15

Multiplying vectors: Dot product

A * B = |A| * |B| cos(theta)

Results in only a scalar quantity

16

Multiplying vectors: Cross product

A x B = |A| |B| sin (theta)

includes vector quantity so the angle as well

17

Determining direction using right hand rule

Start by pointing your thumb in direction of first vector

Extend your fingers in direction of next vector

You palm establishes the plane between the two vectors - direction it points is direction of C

Used to find cross product resultant vector

18

Difference between average speed and average velocity

But the instantaneous speed and velocity will always have the same magnitude

Average speed deals with distance traveled over time while average velocity deals with displacement (from origin) over time (could be zero in an orbit)

19

Gravitational force

Gm1m2/r^2

20

Static friction

Between stationary object and surface the object is on

0 <_ fs <_ usN

coefficient of static friction times the normal force

Need to surpass threshhold

21

Kinetic friction

fc = ukN

us is always larger than uk

22

F = m x a

A body either at rest or in motion with constant velocity will remain that way unless a net force acts upon it

23

Kinematics equations

v = v0 + at

x = v0t + (at^2)/2

v^2 = v0^2 + 2ax

x = vt (vector v)

24

acceleration due to gravity

g = 9.8 m/s^2

...

25

projectile problems

remember constant horizontal velocity, no horizontal acceleration

26

Centripetal force equation for uniform circular motion

Fc = mv^2/r

27

Centripetal acceleration equation

a = v^2/r

28

torque equation

fixed pivot point is the fulcrum

"equilibrium" = not rotating

t = r x F = rF sin(theta)

r is length of lever arm and F is magnitude of force

theta is the angle between lever arm and force vectors

29

a moving object can be in equilibrium

translational equilibrium requires net force on object to be 0, (constant vel) but the rotational equilibrium is when the torque equals zero or the centripetal a is zero