What’s the velocity of a bike ride taking 45 mins over a distance of 4km

The speed of the ride is

Speed = (distance covered) / (time to cover the distance)

Speed = (4,000 m) / (45 min)

Speed = 88.89 m/s

Speed = 1.481 m/s

Speed = 5.333 km/hr

There's not enough information given in the question to calculate the velocity of the ride.  For example ...

-- If the ride was completely in a straight line, then the velocity would be exactly equal to the speed.

-- If the rider went 2km from his house and then 2km back home again, his velocity for the whole ride would be zero.

We just don't know from the information given.

molecules are free to separate from each other and will take on the shape of the container. molecules move completely at random and high speeds. they vibrate in a fixed position and do not move around much. molecules expand to the edge of their container.