Definition:

Speed = Distance travelled per unit time

Speed=DistanceTime\text{Speed} = \frac{\text{Distance}}{\text{Time}}Speed=TimeDistance

Important Points:

• It has no direction

• It is a scalar quantity

• It is always positive

Example:

If a car travels 100 m in 10 s:

Speed=10010=10 m/s\text{Speed} = \frac{100}{10} = 10 \text{ m/s}Speed=10100=10 m/s

We only know how fast — not where.

🔹 2️⃣ Velocity

✅ Definition:

Velocity = Displacement per unit time

Velocity=DisplacementTime\text{Velocity} = \frac{\text{Displacement}}{\text{Time}}Velocity=TimeDisplacement

Important Points:

• It has direction

• It is a vector quantity

• It can be positive, negative, or zero

Example:

If a car moves 10 m/s east, that is velocity.

Direction matters.

🎯 Key Difference

🧠 Simple Example to Understand

Suppose you walk:

• 5 m forward

• Then 5 m back

Distance = 10 m
Displacement = 0 m

If total time = 10 s:

Speed = 10/10 = 1 m/s
Velocity = 0/10 = 0 m/s

👉 You moved, so speed is not zero.
👉 But you ended where you started, so velocity is zero.

📌 Average Speed vs Average Velocity

Average Speed:

Total DistanceTotal Time\frac{\text{Total Distance}}{\text{Total Time}}Total TimeTotal Distance

Average Velocity:

Total DisplacementTotal Time\frac{\text{Total Displacement}}{\text{Total Time}}Total TimeTotal Displacement

They are equal only in straight-line motion without changing direction.

🚀 In Simple Words

Speed tells:

“How fast?”

Velocity tells:

“How fast and in which direction?”