Velocity & Acceleration

• Physics
• Secondary Education

Velocity & Acceleration

No, they are not the same thing...

• Many people confuse the two.
• Velocity is simply the speed of an object in a particular direction.
• Acceleration is the rate of the change in velocity, which means something is either slowing down or speeding up. 

What is Velocity?

• Vector quantity
• Speed at which something moves in a particular direction.
• Measures displacement

Velocity Formula

                                                                                        

                                                                     v = velocity

                                                                    d = distance

                                                                     t = time 

v=​t​​d​​

What is the S.I. Unit for Velocity?

Because: 

Unit for distance is m (meters)

Unit for time is s (seconds)

​s​​m​​

Let's Practice!

A car travels at uniform velocity a distance of 100 m in 4 seconds. What is the velocity of the car?

First step:

Write the equation for velocity

v=d

      t

Next, define your variables:

d = 100m

t = 4s

Now you can plug your variables into your equation:

v = 100

       4

Work out the problem

v = 100

     4

v = 25 

​s​​m​​

What is Acceleration?

• Vector quantity
•  The rate at which an object changes its velocity over a period of time.

REMEMBER:

Vector quantity of the rate and direction of motion. In simpler terms, it is the speed at which something moves in one direction.

Acceleration Formula

a = acceleration

    v = change in velocity (v^f {final} - vⁱ {initial})

    t = change in time 

(t^f {final} - tⁱ {initial})

What is the S.I. Unit for Acceleration?

       

^{(meters per second squared)}

Because:

 Unit for velocity is        

Unit for time is seconds

​s​​m​​

​s​​m​​

2

Keep in mind

• Subtract initial velocity from final velocity. If you do it in reverse, your acceleration will be incorrect.
• If the final velocity is less than the initial velocity, you will have a negative number which means the object slowed down.
• If you do not have a starting time, use zero (0). 

Let's Practice

A delivery truck accelerates from 20       to 40        in 4 seconds. What is its average acceleration?

First, write out your equation

a = v (f) - v (i)

       t (f) - t (i)

​s​​m​​

​s​​m​​

Next, define your variables

v (f) = 40 

v (i) = 20

t (f) = 4s

t (i) = 0s

​s​​m​​

​s​​m​​

Plug your variables into the equation

                                                       a =  40 - 20

                                                                 4 - 0   

                                                          a = 20

                                                                  4

                                                          a = 5

  

​s​​m​​

2

CONGRATULATIONS

You have successfully learned about velocity & acceleration.