(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

you're driving down the highway late one night at 20ms when a deep steps onto the road 35m infront of you. your reaction time before steeping on the brakes is 0.5s and the max deceleration of ur car is 10m/s^2

what is the max speed you could have and still not hit the deer?

deltaX=35m V=?

a=-10m/s^2 reaction time = 0.5s

2. Relevant equations

Xf= Xi+ViT+1/2aT^2

Vf-Vi=aT

Vf^2=Vi^2+1/2a(deltaX)

3. The attempt at a solution

so this is what i tried

i pluged the numbers into the first equation to get

35=0+ViT+1/2(-10)T^2

and i have 2 missing variables so i tried to get it from the other equation

Vf-Vi=aT

0-Vi=(-10)T then that didnt work so i tried the other equation

Vf^2=Vi^2+1/2a(deltaX)

0=Vi^2+1/2(-10)35

Vi= 13.23m/s

and i know that Vi can't be right because i did the question before it and it had Vi of 20m/s and it was 5m from hitting the deer...i dont know what i did wrong can someone help please?

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

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# Homework Help: Kinematics, driving question

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