Question

During the summer, when your lawn is growing quickly, estimate this speed, in m/s. Make this estimate from your experience noting, for instance, how often you mow the lawn and what length you trim.

Answer 1

Answer: If T is the time you wait to trim the lawn since you last did it and B is the lenght at which you trim, then the speed will be:

`v=(B)/(T)`

Step-by-step explanation:

Let's say T is the time you wait to trim the lawn since you last did it (1 month for example) and B is the lenght at which you trim (10cm for example).

If v is the speed at which the lawn grows, then the lenght of the lawn as a function of time will be:

`b(t)=b_(0)+ vt`

where
`b_(0)` is an arbitrary initial lenght. Let's say
`b_(0)=0`.

`b(t)=vt`

Then we have:

`v=(b(t))/(t)`

So, at time T the lawn has grown a lenght B. And the speed is:

`v=(B)/(T)`