Distinguish between speed and velocity.

Ali,while driving to school,computes the average speed for his trip to be $20 \, km \, h^{-1}$. On his return trip along the same route,there is less traffic and the average speed is $30 \, km \, h^{-1}$. What is the average speed for Ali's entire trip?

Define 'average speed'. An object moves with a uniform speed of $10\, m s^{-1}$ for $5\, s$ and then with a uniform speed of $5\, m s^{-1}$ for $10\, s$. Find its average speed.

All buses and cars these days are fitted with a speedometer,which shows the velocity of the vehicle. $A$ device called odometer records the distance moved by the vehicle. If the reading on the odometer of a vehicle in the beginning of a trip and after $40 \text{ minutes}$ were $1048 \text{ km}$ and $1096 \text{ km}$ respectively,calculate its average velocity. Will the reading on the speedometer show this velocity when the vehicle is moving? Support your answer with reason.

What is the average velocity of a particle when it returns to the starting point? Can its average speed be zero?

Which of the following is not a vector?