A 5.2 × 105 kg subway train is brought to a stop from a speed of 0.55 m/s in 0.51 m by a large spring bumper at the end of its track. What is the force constant k of the spring in N/m?

A 52 105 kg subway train is brought to a stop from a speed of 055 ms in 051 m by a large spring bumper at the end of its track What is the force constant k of t class=

Respuesta :

Given:

The mass of the subway train is,

[tex]m=5.2\times10^5\text{ kg}[/tex]

The initial speed of the train is,

[tex]v=0.55\text{ m/s}[/tex]

The distance moved by train is,

[tex]x=0.51\text{ m}[/tex]

To find:

the spring constant

Explanation:

The kinetic energy of the train converts into the potential energy of the spring. So we can write,

[tex]\begin{gathered} \frac{1}{2}kx^2=\frac{1}{2}mv^2 \\ k=\frac{mv^2}{x^2} \end{gathered}[/tex]

Substituting the values we get,

[tex]\begin{gathered} k=\frac{5.2\times10^5\times0.55^2}{0.51^2} \\ =0.60\times10^6\text{ N/m} \end{gathered}[/tex]

Hence, the spring constant is

[tex]0.60\times10^6\text{ N/m}[/tex]