Symbols
a = acceleration
t = time
d = distance
s = speed
Ѵ = velocity (& speed)
Ѵi = initial(beginning) velocity
Ѵf = final(ending) velocity
Δ = change(Delta)
ΔѴ = change in velocity
g = gravity's acceleration 9.8 cm/sec
deceleration(-a): to slow down
*Note: To calculate deceleration (slow down) use the
acceleration equations but remember: deceleration is negative.
Formulas/Equations
To calculate final velocity:
Ѵf = Ѵi + at
(Final velocity) = (Initial Velocity) + (acceleration x time)
To calculate initial velocity:
Ѵi = Ѵf - at
(Initial velocity) =(Final Velocity) - (acceleration x time)
To calculate change in velocity:
Δ Ѵ = Ѵf - Ѵi
(Change in Velocity) = (Final Velocity) - (Initial Velocity)
To calculate acceleration:
a = ΔѴ/t
(acceleration) = (Change in Velocity divided by time)
*Note: To calculate deceleration (slow down) use the
acceleration equations but remember: deceleration is negative.
To calculate time:
t = Δ Ѵ/a
(Time) = (Change in velocity divided by acceleration)
Freefall
g = gravity's acceleration
g = 9.8m/sec2
(g = 10m/sec2 is often used in math calculations)
v = velocity/Speed
(Instantaneous speed in freefall)
t = time (time elapsed from start to finish of fall)
Formulas for Freefall
To calculate velocity(Instantaneous speed) :
v = gt
(velocity/speed)= (gravity's acceleration x time elapsed)
To calculate acceleration through gravity:
g = v/t
(gravity's acceleration) = (velocity) divided by (time)
To calculate time (elapsed):
t = v/g
(time) = (velocity) divided by (gravity's acceleration)
To calculate distance:
d = Ѵit+ ½ gt2
(distance) = (initial velocity X time) + ½ ( gravity's acceleration x time squared )
To calculate distance:
d = ½ (Ѵf+Ѵi)t
(distance) = ½ (final velocity + initial velocity) x time
Vocabulary
force
Definition: The push or pull one object exerts on another so that an action can take place
Context: Throughout the day, we exert force on different objects: pressing with a pencil, lifting a backpack,
and pulling a zipper up.
mass
Definition: total quantity of an object's matter
motion
Definition: movement of an object
velocity
Definition: rate of motion in a particular direction
acceleration
Definition: the act of speeding up
deceleration
Definition: the act of slowing down
gravity
Definition: universal force of the attraction of the mass of an object
Context: The motion of objects has long been a fascination, but it was the
Italian physicist Galileo who first began a scientific inquiry into
the behavior of moving objects. He studied the speed of falling
bodies and determined all objects fell at the same rate of speed
regardless of their weight.
constant
Definition: always the same; unchanging
Context: Acceleration in freefall or rate of speed (gravity) is constant. g=9.8m/sec2
friction
Definition: The force of one surface rubbing against another, with the total effect being to decrease motion
Context: If you want ski quickly down a slope, adjust your weight so little friction exists between the skis and
the snow.
frictionless
Definition: There is no force present that resists the relative motion of an object.
Context: Calculate the velocity of a falling object in a "frictionless" environment.
energy
Definition: The capacity for doing work, such as changing position or covering a certain distance
Context: Without energy, many forces taken for granted, such as fire and electricity, could not be activated.
chemical energy
Definition: Energy stored in chemical bonds, such as in foods or in a flame used to light a fir
Context: While playing baseball, your body transforms chemical energy stored in its cells into energy that you
can use.
kinetic energy
Definition: The energy of moving objects
Context: A skater gliding across an ice rink is demonstrating kinetic energy.
potential energy
Definition: Energy that is stored
Context: Sitting quietly, your body stores potential energy that can be used when you get up and move
around.
slope
Definition: to direct at a slant or inclination; incline from the horizontal or vertical
Context: The line's slope on my graph is steep.
steep
Definition: having an almost vertical slope or pitch, or a relatively high gradient, as a hill, an
ascent, stairs, etc.
Context: The line's slope on my graph is steep.
gradual
Definition rising or descending at an even, moderate inclination
Context: The line's slope on my graph is gradual.