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A runaway train car that has a mass of 15,000 kg travels at a speed of 5.4 m/s down a track. Compute the time required for a force of 1500 N to bring it to rest.
(a) 0.019 s
(b) 54s
(c) 4.2Ã106s
(d) 2.4Ã10â7s

Respuesta :

Answer:

54 s

Explanation:

Given that,

Mass of a car, m = 15000 kg

Initial speed, u = 5.4 m/s

Final speed, v = 0 (it comes to rest)

Force, F = 1500 N

We need to find time when it comes to rest. Let it is t. Net force is given by :

F = ma, a is acceleration of the car

[tex]F=\dfrac{m(v-u)}{t}\\\\t=\dfrac{m(v-u)}{F}\\\\t=\dfrac{15000\times (0-5.4)}{1500}\\\\t=54\ s[/tex]

So, it will take 54 seconds to come to rest.

asuwafohjames

The time required to bring the car to rest is 54 s and the right option is (b) 54 s.

To calculate the time required for the force to bring the car to rest, we use the formula below.

Formula:

  • F = m(v-u)/t............ Equation 1

Where:

  • F = Force applied to the car
  • m = mass of the car
  • v = final velocity of the car
  • u = initial velocity of the car
  • t = time.

Make t the subject of the equation

  • t = m(v-u)/F............. Equation 2

From the question,

Given:

  • F = -1500 N (stopping force)
  • m = 15000 kg
  • v = 0 m/s (to rest)
  • u = 5.4 m/s

Substitute these values into equation 2

  • t = [1500(0-5.4)]/-1500
  • t = -81000/-1500
  • t =  54 seconds
  • t ≈ 54 s

Hence, The time required to bring the car to rest is 54 s and the right option is (b) 54 s.

Learn more about time here: https://brainly.com/question/4931057

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