Linear Motion + Free Fall

Kinematics

the mathematical treatment for the motions of the bodies without regard to the forces that produce the motion.

Distance (d)

actual length travelled on a given path

Displacement (Δx)

linear distance between the starting point and end point of travel

Scalar

physical quantity with only a magnitude (no direction)

Examples of scalar

distance, time, mass, speed, kinetic energy, temp

Vector

a physical quantity has both direction and magnitude

Examples of vector

displacement, velocity, force, acceleration, momentum

Speed

rate of change and distance

What do you find out?

Speed

Velocity

rate of change in displacement

What does this find?

Velocity

Average Velocity

Average rate of change in displacement over a given period of time

Instantaneous velocity

actual velocity at any one instant

Vo

initial velocity at beginning of time period

Vf

final velocity at the end of the given time period

Example of an instantaneous speed found in your car?

Speedometer

Acceleration (a)

rate of change in velocity

Unit of acceleration

m/s²

Is acceleration a vector or scalar quantity?

Vector

What does this find?

acceleration

How to find Vf?

Vo+at

Can an object have acceleration but have a velocity of zero?

Yes, throwing a ball straight up

Can an object have a velocity but have an acceleration of zero?

Yes, constant velocity

Is negative acceleration teh same thing as deceleration?

Nope, not at all

When your velocity is +, and so is your acceleration, you are…

Speeding up

When your velocity is -, and so is your acceleration, you are…

speeding up (in the negative direction)

If you have - velocity but + acceleration, you are…

slowing down (in the negative direction)

If you have + velocity but - acceleration, you are

slowing down (while moving forward)

What does this find?

Average Velocity

What does this find?

Change in Displacement

What does this find?

V Final Squared

Gravity (g)

the natural, universal physical force of attraction that pulls together all objects that have mass or energy;acceleration that an object will experience from a large celestial object

What is the force of gravity? (aka the acceleration of gravity?)

a=g= -9.81 m/s²

Free Fall

he motion of an object when gravity is the only force acting upon it, with all other forces—like air resistance and friction—ignored

What are the assumed characteristics of objects in free fall?

They will encounter no air resistance, and acceleration is always -9.81 m/s²

If the factors of free fall differ, how would the rate of free fall be effected?

In true free fall the rate is identical for all objects, but when air resistance is present, differences in mass, shape, surface area, and the density of the medium cause objects to fall at different rates and reach different terminal velocities.

What would the graph look like for a falling ball in terms of displacement?

What would the graph look like for a falling ball in terms of velocity?

What would the graph look like for a falling ball in terms of acceleration?

How does mass effect free fall?

It doesn’t, since we neglect air resistance…but in the real world, it does

What are the three types of free fall?

Dropping, Thrown Down, and Thrown Up

When you drop a ball, what is the a, Vo, Vf.

a=-9.81 m/s², Vo=0 m/s, Vf=0 m/s (but we measure max velocity)

When you throw a ball down, what is the a, Vo, Vf

a=-9.81 m/s², Vo=not 0, Vf=max velocity

When you throw a ball up, what is the a, Vo, Vf

a=-9.81 m/s², Vo=max velocity, Vf=0 m/s

What are the two different graphs that are interpreted in this unit?

Velocity vs. Time and Displacement vs. Time

Magnitude

the size, quantity, or strength of a physical measurement, expressed as a number with a unit, without regard to its direction