What is the difference between an odometer and speedometer. Name two time measuring devices used in ancient times.

Hint: Speed is defined as the ratio of distance and time taken. When a vehicle is moving with some speed and we need to know at which speed the vehicle is moving then we use different devices for sensing speed.

Complete step by step solution:
It is asked in the problem about the difference between odometer and speedometer. The odometer is the device which is used to measure the distance travelled. The distance travelled by vehicle between any two points can be known by the odometer. The speedometer is the device which can tell us the instantaneous speed of any vehicle. The speedometer is used to get the speed for instantaneous speed measuring.

Additional information: When vehicles were produced and the people started to use then the need of the speedometer was observed for the calculation of the speed and also the need for the calculation of the distance travelled was also observed by the people and then the odometer was invented. The odometer calculates the distance travelled by the vehicle and it is done by calculating the number of rotations done by the vehicle and this is fixed into the device of odometer so whenever the a number of rotations done by the wheel equals to 1km the odometer shows 1km distance.

Note: The importance of speed calculation is very much as we can tell at time will the vehicle cover a given distance we can also calculate what speed we should move so that we reach a particular place at given.