# Calculating Stopping Distance from starting speed and constant deceleration

• Jan 5th 2009, 07:30 AM
Milly_Bristol
Calculating Stopping Distance from starting speed and constant deceleration
I know this is simple but I can't remember how to do this at all! Just going over antiderivatives...

Starting speed = 55mph (straight road)
Constant deceleration = 11ft/s^2

How do I work out the stopping distance?

Thanks for any help!!
• Jan 5th 2009, 07:41 AM
skeeter
convert $v_0 = 55 \, mph$ to $ft/sec$

$v(t) = v_0 - 11t$

calculate the amount of time it takes to stop ... $t_s$

stopping distance = $\int_0^{t_s} v(t) \, dt$

note that the stopping distance is very easy to calculate with a velocity graph.