Question

A motorist travels a distance of 406 km during a 7 hr period. What was the average speed in (a) km/hr and (b) m/sec?

Answer 1

The motorist travels (a) 58 km/h and (b) ~16.1 m/sec

Answer 2

The average speed was 58
`(km)/(hr)` or 16.11
`(m)/(sec)`

Step-by-step explanation:

Speed ​​is a physical quantity that expresses the relationship between the space traveled by an object, the time used for it and its direction. Its unit of measurement in the International System (S.I.) is the meter per second
`(m)/(s)`.

So:

`speed=(distance)/(time)`

In this case you know:

• distante= 506 km
• time=7 hr

Replacing:

`speed=(406 km)/(7 hr)`

Solving:

`speed=58 (km)/(hr)`

Taking into account that 1 km is 1000 m and 1 hour is 60 minutes, which in turn is 60 seconds, the unit conversion is performed:

`speed= 58(km)/(hr) * 1 000(m)/(km) *(1)/(60) (hr)/(minutes) *(1)/(60) (minute)/(sec)`

`speed=16.11 (m)/(sec)`

The average speed was 58
`(km)/(hr)` or 16.11
`(m)/(sec)`