# Thread: word problem - the snow plough problem?

1. ## word problem - the snow plough problem?

so far I have derived this general equation dl/dt= amountplowed/( intial snow depth + rate of snowfall*t)
not sure if it's correct

One morning in a certain town, it begins to snow steadily. At 8:00am a snowplow sets out t
ear the highway. It can clear a constant amount of snow per unit time, which means that if th
ow is twice as deep then the plow will move half as quickly. Suppose that the snow plow clear
wo miles of the highway by 11:00am, and by 2:00pm it has cleared only another 1 mile.
1. At what time did it start snowing? (Hint: This is a di erential equations class, so yo
probably need to write down an appropriate di erential equation to model the situation an
then solve the di erential equation to evaluate the unknown constants in the equation.)
2. List explicitly all of the assumptions that you made in order to write down your di erentia
equation in part (1). State whether each assumption seems realistic to you or not.
3. Suppose now that a second snowplow starts clearing the same road at 9:00am. Will th
second snowplow crash into the rst snow plow? If so, when?
4. Is it possible to avoid a crash if the second snowplow changes the time at which it starts out

2. ## Re: word problem - the snow plough problem?

Originally Posted by wrongturn12
so far I have derived this general equation dl/dt= amountplowed/( intial snow depth + rate of snowfall*t)
not sure if it's correct

One morning in a certain town, it begins to snow steadily. At 8:00am a snowplow sets out t
ear the highway. It can clear a constant amount of snow per unit time, which means that if th
ow is twice as deep then the plow will move half as quickly. Suppose that the snow plow clear
wo miles of the highway by 11:00am, and by 2:00pm it has cleared only another 1 mile.
1. At what time did it start snowing? (Hint: This is a di erential equations class, so yo
probably need to write down an appropriate di erential equation to model the situation an
then solve the di erential equation to evaluate the unknown constants in the equation.)
2. List explicitly all of the assumptions that you made in order to write down your di erentia
equation in part (1). State whether each assumption seems realistic to you or not.
3. Suppose now that a second snowplow starts clearing the same road at 9:00am. Will th
second snowplow crash into the rst snow plow? If so, when?
4. Is it possible to avoid a crash if the second snowplow changes the time at which it starts out