A 5.18x10^4 kg railroad car moves on a frictionless horizontal rails until it hits a horizontal spring stopper with a force constant of 4.21x10^5 N/m. When the railroad car comes to a complete stop, the compression of the spring stopper is 32 cm. How fast was the railroad car initially?

The initial velocity of the cart was 0.91m/s.

Explanation:

When the car comes to a stop it has delivered all of its kinetic energy to the spring; therefore,

solving for we get:

we put in , , and to get:

energy stored in the capacitor= 9.72 x 10⁻⁴ j

explanation:

the energy stored in the capacitor is given by

e= 1/2 c v²

e= energy stored

c= capacitance= 1.5 µc= 1.5 x 10⁻⁶f

v= potential difference=36 v

so energy stored= e= 1/2 (1.5 x 10⁻⁶) (36)²

energy stored= 9.72 x 10⁻⁴j