1 A certain passenger train, whose total weight is $P=18 \times 10^{4} \mathrm{~kg}$, starts on a horizontal track where $\rho=0.005$ and reaches its maximum speed: $v=12 \frac{\mathrm{m}}{\mathrm{sec}}$ in $t=1$ minute. How far does it travel until it reaches its maximum speed (assuming the motion is uniformly accelerated)? What is its power in horsepower?[^0]


[^0]:    ${ }^{1}$ In this problem, $\rho$ is the coefficient of friction, and $e$ is the sine of the angle of inclination.
$$
s=\frac{a}{2} t^{2} \quad \text { and } \quad a=\frac{v}{t}
$$

from this:

$$
s=\frac{v}{2} t=360 \mathrm{~m}
$$

1 minute of work $1645000 \mathrm{mkg}$

power $=366$ horsepower.

(Gráf Vilmos, Budapest.)

The problem was also solved by: Bánó L., Ehrenstein P., Fekete M., Grünhut H., Haar A., Jánosy Gy., Koritsánszky I., Schwarz O., Székely J.