What net external force is required to accelerate a 155kg automobile form rest to a speed of 100km/hr in 10 seconds?

Force = (mass) x (acceleration)The mass is easy ... it's 155 kg.The acceleration isn't so easy, mainly because of the units.In order to get a force in newtons, the acceleration has to be in m/s². That will take some work.Acceleration = (change of speed) / time = (100 km/hr) / (10 sec).(100 km/hr) x (1,000 m/km) x (1 hour / 3,600 sec) = 1000/36  m/sAcceleration = (1000/36 m/s) / (10sec) = (100/36)  m/s²Force = (mass) x (acceleration) =            (155 kg) x (100/36 m/s²) =                     15,500/36  kg-m/s²  =  430 and 5/9 newtons =                                               about  96.9 pounds.(That's not much force ... mainly because your car only weighs about 342 pounds.)