What is the speed if distance is 100 km and time is 5 hours?

20 km/h

Speed = Distance / Time = 100 / 5 = 20 km/h. This is the fundamental formula relating speed, distance, and time.

Understanding Physics questions

Physics questions link quantities through a small number of laws. Writing the formula first, then substituting, prevents most errors.

How to approach it

1. List the given quantities with their units.
2. Choose the law or equation that relates them.
3. Convert units to a consistent system before substituting.
4. Check that the final unit matches the quantity being asked for.

Common mistakes to avoid

• Mixing centimetres and metres in the same calculation.
• Treating speed and velocity as identical.
• Ignoring the direction of a vector quantity.

Where it appears: Covered in CBSE Class 8–12 physics, IGCSE and IB Physics.