Gen physics 2205 formulae

Equations including velocity

v = v0 + at

x = 0.5(v0 + v)t

x = v0t +0.5at^2

v^2 = v0^2 + 2ax

Equations involving displacement

x = 0.5(v0 + v)t

x = v0t + 0.5at^2

average speed

total distance/change in time

- scalar quantity

average velocity

displacement/change in time

or

change in displacement/change in time

average speed compared to average velocity

and if an object changes direction at any time

avg speed is >_ avg velocity

total distance vs displacement

total distance >_ displacement

similarities between free fall and projectile motion

both motions involve an object that is only influenced by gravity and has no air resistance

projectile motion is a subset of free fall

free fall is a projectile motion of v_x = 0 (only falls vertically)

in trajectory of projectiles, what remains constant throughout the entire movement

v_x or v in the x axis direction is always constant

when is v_x and v_y equal each other

at the peak of trajectory motion

v_x is always constant; a change in v_x would imply an acceleration

v_y is zero as there is no change in direction because the object has stopped moving

if an object has a velocity of 45m/s at take off, what is the velocity when it returns to the ground?

-45 m/s

when a ball is pushed off a table vs when a ball is dropped from vertically from the table, which hits the ground first

HAHA trick question!

They both hit the ground at the same time because they are independent of one another and are subject to gravity

Range equation

r = (v_0^2 sin 2(theta))/g

Peak of a Trajectory

x coordinate at point = 0.5R

y coordinate at point =

(v_0^2 sin^2 (theta))/2g

time at point =

(v_0 sin (theta))/g

what do forces require

an agent (creates the force)

an object (receives the force)

contact vs long range forces

contact = force directly touches an object (pushing a book)

long range = doesnt directly touch object (gravity)

Does tension pull or push

tension always pulls

what is normal forces

a force perpendicular to surface that equals the force of the object resting on it

eg: a book resting on a table has a normal force equivalent of the force it is acting on the table

types of friction

Static: prevents motion relative to another surface; points in direction that prevents slipping

Kinetic: opposes, but doesnt prevent motion; points in the opposite direction of motion

static friction formula

f_s_max = (u_s)(N)

when the pulling force is greater than f_s_max what happens to the position of the object

the object begins to move

kinetic friction formula

f_k = (u_k)(N)

Newton's Third Law

For every action there is an equal and opposite reaction

force involves 2 interacting bodies

is gravity and normal force an example action-reaction force

nope. action reaction has to be pair of forces that act on different objects

force on book due to table and force on table due to book is an action reaction force

uniform circular motion concepts

v = Rw

FYI w = angular velocity

velocity points tangential to trajectory and is always perpendicular to radius

acceleration points towards center and there is no tangential acceleration which means the net force is also pointing inwards

3 fundamental equation for uniform circular motion

v = Rw

wT = 2pi

fT = 1

FYI T = period; time requited to make 1 full revolution

Vmax =

sqrt((µs)(g)(r))

what units are period, angular velocity, and fruquency

period = sec, min, sec/rev

angular velocity = rad/s

frequency = rpm, rev/sec, Hz (1/s)