thschica

On both of these I got the right answer but it was so long ago I have no idea how to do them.
(Which equation am I to use?)(v=Vo+at? if so how?)
1.Determine the stopping distances for an automobile with an initial speed of 91 km/h and human reaction time of 3.0 s for the following accelerations.
(a) a = -4.0 m/s2
? m
(b) a = -8.0 m/s2
? m
(This one is beyond me I keep attempting to use equations but none of them are working)
2.5. A football is kicked at ground level with a speed of 20.0 m/s at an angle of 38.0° to the horizontal. How much later does it hit the ground?
? seconds