An engine pulls a train of 20 frieght cars each having a mass of 5.0*10^4 kg with a constant force. The cars move from rest to a speed of 4.5 m/s in 19.7s on a straight track. Neglecting friction, the force with which the tenth car pulls the eleventh one (at the middle ofthe train) is ____ N in the direction of motion.

Find acceleration.

then, Forceoneleventh= (mass11+ mass12+ ...)a

To find the force with which the tenth car pulls the eleventh car, we need to apply Newton's second law of motion, which states that the force acting on an object is equal to its mass multiplied by its acceleration.

In this case, the tenth car is exerting a force on the eleventh car. Since the cars are connected in a straight line, the force applied by the tenth car on the eleventh car is the same as the force exerted by the eleventh car on the tenth car, according to Newton's third law of motion.

To calculate the force, we first need to find the acceleration of the entire train. We can use the kinematic equation:

v = u + at

where:
v = final velocity of the train (4.5 m/s)
u = initial velocity of the train (0 m/s)
a = acceleration of the train
t = time taken (19.7 s)

Rearranging the equation, we get:

a = (v - u) / t

Substituting the given values:

a = (4.5 m/s - 0 m/s) / 19.7 s
a = 0.228 m/s^2

Now that we have the acceleration of the train, we can calculate the force using Newton's second law:

F = m * a

where:
F = force
m = mass of the eleventh car (5.0*10^4 kg)

Substituting the values:

F = (5.0*10^4 kg) * (0.228 m/s^2)
F = 1.14*10^4 N

Therefore, the force with which the tenth car pulls the eleventh car is 1.14*10^4 N in the direction of motion.