An engineering student is driving on a level roadway and sees a construction sign

S $=185$m ahead in$.$ the middle of the roadway. The student strikes the sign at a

speed of V $=63$km$/$h$.$ If the student was travelling at $90$ km$/$h when the sign was first

spotted, what was the student's associated perception$/$reaction time? How far back should the student have first observed the sign to be able to stop safely at a comfortable deceleration rate before hitting the sign? $(3$ decimal places$)$

$(1)$ The perception$/$reaction time t$=$

S

$(2)$ The stopping sight distance SSD$=$

m