Math question

[SKMMAN]

A goalkeeper has a reaction time of 0.4 s. A puck travelling at 25 m/s bounces off a player without losing speed. How far away from the goalie must this occur to give the goalie a chance of stopping the puck?

 

[spicypumpkin]

Well assuming that his reaction time were 1 second, it would take 25 meters of it traveling for him to catch it. Since his reaction time is .4 seconds, multiply 25 times .4 and you've got your answer, 10 meters.

 

[SKMMAN]

Thanks! I was getting confused trying to solve this. Are you good at physics?

 

[spicypumpkin]

I used to be when I took the class 2 years ago. What's the question?

 

[LeiYunFat]

Unit analysis, SKM. Just look at what you have and look at what you're trying to find. Certain things will cancel out, and the units are a good indicator of that. Don't let those damn word problems get the better of you

 

[SKMMAN]

What do you mean?

 

[SKMMAN]

Unit analysis, SKM. Just look at what you have and look at what you're trying to find. Certain things will cancel out, and the units are a good indicator of that. Don't let those damn word problems get the better of you

I was having a hard time with this question because I was wondering what math formula I needed to use, but word problems do piss me off.

 

[LeiYunFat]

Well that's what unit analysis is for. There is no set "formula" that you can just plug in and get it...it's more like a comprehensive formula.


You're given:

Speed (m/s)
Speed reaction (s)

You need:

Distance (m)

Since seconds (s) is on the bottom, multiplying by seconds on top will cancel them out, leaving only distance (m).