7. A locomotive is pulling 19 freight cars, each of which is loaded with the same amount of weight. The mass of each freight car (with its load) is 37,000 kg. If the train is accelerating at 0.22m/s2 on a level track, what is the tension in the coupling between the second and third cars

N 138380

Explanation:

Force = ma where m is the mass in kg and a is acceleration

the locomotive is pulling 19 freight cars mass of each car is 37 000 kg

the train accelerating at 0.22 m/s²

the tension in the coupling between the second and third cars = the tension between the second and third cars pulling the third car to the 19 th car = 17 × 37000 kg × 0.22 m/s² = N 138380

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.