A 3500kg car traveling to thenorth is slowed down uniformly from an initial velocity of20m.s by a 6250N braking force acting opposite the car'smotion. Use the impulse-momentum theorem to answer the followingquestions: a)What is the car's velocity after 2.5s? b)How far does the car move during 2.5s? c)How long does it take the car to come to a completestop? A 3500kg car traveling to thenorth is slowed down uniformly from an initial velocity of20m.s by a 6250N braking force acting opposite the car'smotion. Use the impulse-momentum theorem to answer the followingquestions: a)What is the car's velocity after 2.5s? b)How far does the car move during 2.5s? c)How long does it take the car to come to a completestop?
Explanation / Answer
We know force = impulse * time F = m ( v - u ) * t where F = - 6250 N m= mass = 3500 kg u= Initial velocity = 20 m / s t = time = 2.5 s So, car's velocity after 2.5 s is v = ( F / m t )+ u =19.28 m / s (b). From the relation v 2 - u 2 = 2aS from this distance covered S = [ v 2 - u2] / 2a where a = accleration = F / m (c). required Time t = ( v - u ) / a substitue values weget answers