# Homework Help: How long will it take to mow a football field?

1. Sep 9, 2011

### BuhRock

1. Estimate how long it would take one person to mow a football field using an ordinary home lawn mower. Assume the mower moves at 1 km/h and has a .5m width.

2. Are we using a football field with dimensions of 300ft by 160 ft?
Will I need to find the area of the field in m^2?

3. I converted ft into meters so I have the length of the field to be 91.44 meters and the width is 48.8 meters. After this part, I'm not sure what to do. Would you get the area and then divide by .5?

2. Sep 9, 2011

### xts

OK. You made a first step - converting units to metric...

You are almost right, saying that you should divide area by the mowing width. You forgot to divide it also by mower speed to obtain the total time.

If you want to be more precise, you should notice, that the last pass of the mower won't be fully efficient. If you go with your mower along the field, then you need not 97.6, but 98 passes. Even if you mow only half of mower width, you still walkk with the same speed.
Each pass takes 91.55m/(1km/h) = 0.09155 hour. Plus some time you need to turn - 5s maybe? So the total time is 98*0.09155h + 97*5s = 9.46h. To be not too precise: 9.5h is the first estimate. Add a half hour for two short breaks (the worker may not eat for the whole day, but should be allowed to [Obscenity removed] at least...) - you have 10 hours.

Last edited by a moderator: Sep 12, 2011
3. Sep 9, 2011

### BuhRock

Where did the 98 come from?

4. Sep 9, 2011

### xts

98?
Width of the field is 48.8m. And in one pass you make 0.5m

5. Sep 12, 2011

### Hootenanny

Staff Emeritus
Although this may come a little late, xts' response is incorrect. You are given no information regarding the turning of the mower, nor worker breaks, you should therefore neglect any break times or the time required to turn the mower.