Lesson 3 — doing calculations

• Speed
• Middelbare school
• havo, vwo
• Leerjaar 2

TTO 2 – Science

Chapter 4. Speed

Learning goals

• You can explain the difference between steady and average speed.
  

• You can name the formula for speed.
  

• You can rearrange the formula for speed.
  

• You can use the formula for speed to do different kinds of calculations.
  

What is speed?

The highest speed possible in the universe?

The speed of light!

The speed of light!

• About 300 000 000 m/s

• About 300 000 km/s

• To be precise: 

      299 792 458 m / s

• In physics its is given the symbol 'c'

Speed

Speed=​time​​Distance​​

v=​t​​d​​

New physical quantity:

Speed

Unit of Speed:

• m/s
• Km/h

Formula

• v: speed (meters/second) m/s)
  
• d: distance (meters) (m)
• t: time (seconds) (s)

The amount of distance something is traveling over a certain time.

Examples:

• A runner is running at a speed of 3/ms
• A car on the highway is driving at a speed of 120 km/h

Doing calculations

When doing calculations, use the following steps:

• Given
  
• Asked
  
• Formula
  
• Calculate
  

Exercise

The space-x rocket called Falcon 9 travels at a speed of 5950 km/h. calculate how many kilometers it would travel in 2,5 days.

Average speed and steady speed

steady speed:

A consistent speed over time.

Average speed:

The average speed over a certain amount of time.

Average speed

avaragespeed=​totaltime​​totaldistance​​

Exercise

Two friends go on a road trip for three days. 

On the first day they travel 765 km in 8,5 hours.

On the second day they travel 660 km in 6 hours.

On the third day they travel 630 km in 9 hours.

Calculate their average speed.

avaragespeed=​totaltime​​totaldistance​​

Homework

Worksheet calculations speed

Exercise 1 - 5