A bus slows down uniformly from 75.0 km/h (21 m/s) to 0 km/h in 21 s. How far does it travel before stopping

In this question two important things are already given. Let us first note them down first.

Speed of the bus = 75.0 km/hr or 21/s

Time before it finally stops = 21second.

It is better to calculate in miles per second as the time given is in second. This will make the problem easier.

We already know that

Distance traveled = Speed * time

= 21 * 21 meters

= 441 meters

So the bus will stop after traveling a distance of 441 meters.

This distance can be converted to kilometer as well very easily now.

1000 meter = 1 km

441 meters = 441/1000 km

= 0.441 km

So the bus will stop after 441 meters or 0.441 kilometers.