- #1
Jennifer001
- 22
- 0
Homework Statement
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
Homework Equations
Xf= Xi+ViT+1/2aT^2
Vf-Vi=aT
Vf^2=Vi^2+1/2a(deltaX)
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 don't know what i did wrong can someone help please?