A car doing 126 km/h brakes steadily and comes to rest in 200 m. How long does it take to stop, in seconds?

expects 11.4 s

24 checks, 0 agreed

draft 24: failed while solving — RuntimeError: no equation determines the time taken of stopping from what is known the engine knows: known: velocity of car at start of stopping from ground; displacement of car during stopping; velocity of car at end of stopping from ground; displacement_a_time(stopping): average velocity of car during stopping == (displacement of car during stopping / time taken of stopping) — not yet known: average velocity of car during stopping; path_a_time(stopping): average speed of car during stopping == (path length of car during stopping / time taken of stopping) — not yet known: average speed of car during stopping; path length of car during stopping; velocity_gained_a_time(stopping): average acceleration of car during stopping == (change of velocity of car during stopping / time taken of stopping) — not yet known: average acceleration of car during stopping; change of velocity of car during stopping; velocity_after_a_time(stopping): velocity of car at end of stopping from ground == (velocity of car at start of stopping from ground + (acceleration of car during stopping * time taken of stopping)) — not yet known: acceleration of car during stopping; position_after_a_time(stopping): position of car at end of stopping == ((position of car at start of stopping + (velocity of car at start of stopping from ground * time taken of stopping)) + ((acceleration of car during stopping * (time taken of stopping ** 2)) / 2)) — not yet known: position of car at end of stopping; position of car at start of stopping; acceleration of car during stopping; mean_of_the_velocities(stopping): (position of car at end of stopping - position of car at start of stopping) == (((velocity of car at end of stopping from ground + velocity of car at start of stopping from ground) * time taken of stopping) / 2) — not yet known: position of car at end of stopping; position of car at start of stopping

solution.rb · draft 24 failed while solving

1solve :car_braking_to_a_stop, using: UniformAcceleration do2  objects :car3  car.goes(:stopping)45  take speed: car.initial_velocity6  take distance: stopping.displacement.magnitude7  deduce_from "comes to rest", car.final_velocity => "0 m/s"8910  time = stopping.time_taken11  answer time:, in: "s", figures: 31213  conclusion "The car slows down at a steady rate, so the time to stop is the distance over the average speed."14end

RuntimeError: no equation determines the time taken of stopping from what is known the engine knows: known: velocity of car at start of stopping from ground; displacement of car during stopping; velocity of car at end of stopping from ground; displacement_a_time(stopping): average velocity of car during stopping == (displacement of car during stopping / time taken of stopping) — not yet known: average velocity of car during stopping; path_a_time(stopping): average speed of car during stopping == (path length of car during stopping / time taken of stopping) — not yet known: average speed of car during stopping; path length of car during stopping; velocity_gained_a_time(stopping): average acceleration of car during stopping == (change of velocity of car during stopping / time taken of stopping) — not yet known: average acceleration of car during stopping; change of velocity of car during stopping; velocity_after_a_time(stopping): velocity of car at end of stopping from ground == (velocity of car at start of stopping from ground + (acceleration of car during stopping * time taken of stopping)) — not yet known: acceleration of car during stopping; position_after_a_time(stopping): position of car at end of stopping == ((position of car at start of stopping + (velocity of car at start of stopping from ground * time taken of stopping)) + ((acceleration of car during stopping * (time taken of stopping ** 2)) / 2)) — not yet known: position of car at end of stopping; position of car at start of stopping; acceleration of car during stopping; mean_of_the_velocities(stopping): (position of car at end of stopping - position of car at start of stopping) == (((velocity of car at end of stopping from ground + velocity of car at start of stopping from ground) * time taken of stopping) / 2) — not yet known: position of car at end of stopping; position of car at start of stopping