## Probability of a rock striking a windshield in a particular location

The windshield of a car has a width of 1067mm and a height of 889mm. The windshield also has a crack with a length of 305mm and a height of 1mm. What is the probability of a rock, with a random trajectory and a measurement of 1mmx1mm, hitting the windshield strikes directly in the center of the crack anywhere along its length?

Am I correct to calculate...?
Possible contact area of the windshield = 948,563mm^2
Possible contact area of the crack = 305mm^2
Probabilty of the rock striking the crack directly in the center of the crack anywhere along its length = 1/948,563(1/305) = 1/289,311,715
...or is it simply 1/948,563 and please explain why the former or the latter is correct
 PhysOrg.com mathematics news on PhysOrg.com >> Pendulum swings back on 350-year-old mathematical mystery>> Bayesian statistics theorem holds its own - but use with caution>> Math technique de-clutters cancer-cell data, revealing tumor evolution, treatment leads
 Recognitions: Homework Help p=Area(crack)/Area(total)=305/948,563

Recognitions:
 Quote by CatastrophicF strikes directly in the center of the crack anywhere along its length?
It isnt clear to me whether the event described is the event that the center of the rock hits the center line of the crack or whether the event is that any point on the rock hits the center line of the crack. (I assume the question isn't whether the center of the rock or some point on it hits the single point that is the "center of the crack".)

## Probability of a rock striking a windshield in a particular location

 Quote by Stephen Tashi It isnt clear to me whether the event described is the event that the center of the rock hits the center line of the crack or whether the event is that any point on the rock hits the center line of the crack. (I assume the question isn't whether the center of the rock or some point on it hits the single point that is the "center of the crack".)
It would be the rock hitting the center line of the crack.

Recognitions: