A1000-kilogram car traveling with a velocity of +20. meters per second decelerates uniformly at -5.0 meters per second2 until it comes to rest. what is the magnitude of the impulse applied to the car to bring it to rest?

Explanation:

Mass of car = 1000 kg

Deceleration = 5 m/s²

Decelerating force = Mass x Deceleration

Decelerating force = 1000 x 5 = 5000 N

We need to find time the time taken to stop

We have equation of motion v = u + at

     Initial velocity, u = 20 m/s

     Final velocity, v  = 0 m/s    

     Acceleration, a = -5 m/s²

     Substituting

                      v = u + at  

                      0 = 20 + -5 x t

                      t = 4s

Impulse = Force x Time

Impulse = 5000 x 4 = 20000 Ns

Magnitude of the impulse applied to the car to bring it to rest is 20000 Ns