A railroad car with a mass of 2000kg is rolling at a speed of 15m/s. What force would be required to stop the car in 10 seconds?
To find the force required to stop the car, we can use Newton's second law of motion, which states that force (F) is equal to the mass (m) multiplied by the acceleration (a). In this case, the acceleration will be negative because we want to bring the car to a stop.
First, let's determine the acceleration using the given information. The initial velocity (u) is 15 m/s, the final velocity (v) is 0 m/s since we want to stop the car, and the time (t) is 10 seconds.
The equation we can use to find the acceleration is:
a = (v - u) / t
Substituting the given values:
a = (0 - 15) / 10
a = -1.5 m/s²
Now that we have the acceleration, we can calculate the force using the formula:
F = m * a
Substituting the given mass:
F = 2000 kg * (-1.5 m/s²)
F = -3000 N
The negative sign indicates that the force required to stop the car acts in the opposite direction to its motion. Therefore, the force required to stop the car in 10 seconds is 3000 Newtons in the opposite direction of its motion.