The electric motor of a model train accelerates the train from rest to 0.640 m/s in 22.0 ms. The total mass of the train is 680 g. Find the average power delivered to the train during its acceleration

F=19.79N

Explanation:

Force F=m×a, a being the acceleration.

a=dv/dt (speed variation/interval of time)

a=(0.640-0)/22ms=

0.640/0.022=640/22=29.1m/s²

Mass: m=680g=0.68kg

Force: F=0.68×29.1=19.79N

The average power delivered to the train is approximately 6.33 watts

Explanation:

Recall that power is defined as the work done (W) per unit of time (t). That is: Power= W/t

in our case the work done is equal to the change in kinetic energy (no potential energy change involved) based on the Kinetic Energy - Work theorem.

The initial kinetic energy is 0 J (the train was at rest, so its velocity is zero), and the final kinetic energy of the system is:

Then the power delivered in 22 milliseconds (which is the same as 0.022 sec) would be:

increasing transnational kinetic energy. because the transnational kinetic energy formula consists of only two variables, mass and velocity, increasing one of those properties is the only way to increase an object's transnational kinetic energy. increases to mass and velocity, however, do not have the same impact.