Speed

How to Calculate Average Speed

*****As you are going over this lesson, you MUST be copying important notes in your notebook. Specially speed definitions, formulas and units****

Calculating Speed, Distance and

Time

One formula 🡪 s = d/t

=

3 different
calculations

For example

Look at these two cars. They both are going to travel a certain distance.

Fill in the Blanks

Different average speeds

Both cars are going to travel a total distance of 4 miles but they both may not reach the destination at the same time.

Open Ended

What are some reasons why both cars might not reach the destination at the same time?

Different Speeds

One driver may drive slower or faster than the other driver.

Different speeds during journey

The drivers may not drive at the same speed throughout the entire 4 miles. Maybe one went 40 miles per hour for the first two miles then went 60 miles per hour for the last 2 miles.

Average Speed

A measurement of the average speed an object traveled takes into account all the variations in speed that may happen during a journey.

Average Speed

The higher an average speed number is, the faster that object completed its journey.

Calculating Average Speed

To calculate the average speed of an object you need to use the avearge speed formula.

Average Speed Formula

The S stands for Average speed

The D stands for Distance

The T stands for Time

Multiple Choice

What does the S stand for in the average speed formula?

• Average Speed

• Distance

• Time

Multiple Choice

What does the D stand for in the average speed formula?

• Average Speed

• Distance

• Time

Multiple Choice

What does the T stand for in the average speed formula?

• Average Speed

• Distance

• Time

Multiple Choice

_____ is how far an object has traveled.

• motion

• distance

• displacement

• speed

Using the avearge speed formula

To calculate the average speed of an object you need to DIVIDE the distance an object traveled by the time. The distance number goes in the calulator first.

Multiple Choice

What number do you put into the calculator first when calculating average speed?

• Speed

• Distance

• Time

Multiple Choice

What do you have to do to the distance and time numbers?

• Divide them

• Multiply them

• Subtract them

• Add them

Calculating Steps - Speed

• Determine what you're solving for.

• Then, write the correct equation to help you solve

  • Speed: Speed = Distance / Time; S = D / T

  • Distance: Distance = Speed x Time; D = S x T

  • Time: Time = Distance / Speed; T = D / S

• Plug in what you know

• Solve for the missing variable

• use correct units

Solve

• First write formula S = D / T

• Plug in 50 for distance

• Plug in 25 for time

• 50 / 25 = 2

• 2 m/s

Lets practice calculating average speed

Use a calculator to help you! You need to score a 70 or above on this assignment to earn credit. You can take it as many times as you need to.

Multiple Choice

A runner races in the 100 meter dash.  It takes her 10 seconds to finish.  What is her average speed?

• 10 m/s
• 1000 m/s
• 100 seconds
• 10 seconds

Multiple Choice

Alan travels 100 km in 5hrs. Find his average speed in km/h

• 5km/hr
• 10km/hr
• 50km/hr
• 20km/hr

Multiple Choice

What two measurements are necessary for calculating speed?

• Mass and time
• Temperature and mass
• Mass and distance
• Distance and time

Multiple Choice

Distance = 360 km

Time = 6 hours

Speed = ?

• 60 kmh

• 50 kmh

• 70 kmh

• 40 kmh

Multiple Choice

Distance = 200 km

Time = 4 hours

Speed = ?

• 40 kmh

• 50 kmh

• 50 km

• 800 kmh

EXIT TICKET

11/8/2024

Multiple Choice

It takes Natalie 0.25 hours to drive to school. Her route is 16 km long. What is Serina’s average speed on her drive to school? Do the work in your notebook.

• 1 km/h

• 4 km/h

• 64 km/h

• 64 mph

Correct Answer : 64 km/h

If it takes Natalie 0.25 hours (time) to drive 16 km (distance), to find the speed you would have to divide the distance by the time.

S = D / T

S = 16 km / 0.25 hours

S = 16/0.25 = 64 (now add your units of measure)

S = 64 km/h

You will now continue to work on Assignment #2 on quizziz, it is a video explanation of how to do the calculations. If there are no headphones available, you may listen to it using a low volume or the captions option.