the brakes of a car provide an acceleration of -5.0 m/s^2 . how long will it take for a car traveling at 20.0 m/s to stop ?
4-seconds.
But if you need to see the math, here you go:
Vf=Vi+at
Where
Vf=0m/s
Vi=20m/s
a=-5.0m/s
and
t=??
Solve for t:
0m/s=20m/s+(-5.0m/s^2)*t
-20m/s=(-5.0m/s^2)*t
t=-20m/s/-5.0m/s^2
t=4s
To find out how long it will take for a car to stop, we need to use the equation of motion:
v = u + at
Where:
v = final velocity (0 m/s)
u = initial velocity (20.0 m/s)
a = acceleration (-5.0 m/s^2)
t = time (unknown)
Rearranging the equation, we get:
t = (v - u) / a
Substituting the given values, we have:
t = (0 - 20.0) / -5.0
Calculating this expression gives us:
t = -20.0 / -5.0
t = 4.0 seconds
Therefore, it will take 4.0 seconds for the car traveling at 20.0 m/s to stop.