1. A train traveling at a speed of 150km/h decelerates for 15 seconds. During that time it travels 400 meters.
A) What is the acceleration? = m/s^2
B) What is its speed after deceleration? = km/h
I need help with which formula to use and how to use it to find the correct answer. Thank you.
To find the acceleration, we can use the following formula:
acceleration = (final velocity - initial velocity) / time
In this case, the initial velocity is 150 km/h, the final velocity is 0 km/h (as the train is decelerating), and the time is 15 seconds. However, before we can use this formula, we need to convert the units of velocity and acceleration to the same system. Let's convert km/h to m/s:
150 km/h * (1000 m / 1 km) * (1 h / 3600 s) ≈ 41.67 m/s
Now, let's plug the values into the formula:
acceleration = (0 m/s - 41.67 m/s) / 15 s = -2.778 m/s² (rounded to three decimal places)
For the speed after deceleration, we don't need any additional formulas. We already know that the velocity after deceleration is 0 km/h since the train comes to a stop. However, if you'd like to convert it to m/s, we can follow the steps we used above:
0 km/h * (1000 m / 1 km) * (1 h / 3600 s) ≈ 0 m/s
Therefore, the speed after deceleration is 0 km/h (or 0 m/s).