Question

Brakes are applied on a car moving at a speed of 80km/h, and stops in 40m. ¿How many meters had it moved in the instant its velocity fell to:
a) 50km/h
b) 25km/h
c) ¿How long did it take to stop?

Answer 1

just plug in for all values and you'll be fine.
v final is not zero, you need to find v final but everything else is given. you need to find time by using x=vi(t). to find acceleration.